Currently the GICv3 driver mandates that platform populate
both G1S and G0 interrupts. However, it is possible that a
given platform is not interested in both the groups and
just needs to specify either one of them.

This patch modifies the `gicv3_rdistif_init()` & `gicv3_distif_init()`
functions to allow either G1S or G0 interrupts to be configured.

Fixes ARM-software/tf-issues#400

Change-Id: I43572b0e08ae30bed5af9334f25d35bf439b0d2b

Introduce AArch32 support for PSCI library

As per the GICv3 specification, to power down a processor using GICv3
and allow automatic power-on if an interrupt must be sent to a processor,
software must set Enable to zero for all interrupt groups(by writing to
GICC_CTLR or ICC_IGRPEN{0,1}_EL1/3 as appropriate.

Also, NonSecure EL1 software may not be aware of the CPU power state
details and fail to choose right states that require quiescing the CPU
interface. So it's preferred that the PSCI implementation handles it as
it is fully aware of the CPU power states.

This patch adds disabling of Group1 NonSecure interrupts during processor
power down along with Group0 and Group1 Secure interrupts so that all the
interrupt groups are handled at once as per specification.

Change-Id: Ib564d773c9c4c41f2ca9471451c030e3de75e641

This patch modifies GICv3 and TZC drivers to add AArch32 support.
No modifications are required for the GICv2 driver for AArch32 support.
The TZC driver assumes that the secure world is running in Little-Endian
mode to do 64 bit manipulations. Assertions are present to validate the
assumption.

Note: The legacy GICv3 driver is not supported for AArch32.

Change-Id: Id1bc75a9f5dafb9715c9500ca77b4606eb1e2458

This patch moves the private GIC common accessors from `gic_common.h` to
a new private header file `gic_common_private.h`. This patch also adds
additional comments to GIC register accessors to highlight the fact
that some of them access register values that correspond to multiple
interrupt IDs. The convention used is that the `set`, `get` and `clr`
accessors access and modify the values corresponding to a single interrupt
ID whereas the `read` and `write` GIC register accessors access the raw
GIC registers and it could correspond to multiple interrupt IDs depending
on the register accessed.

Change-Id: I2643ecb2533f01e3d3219fcedfb5f80c120622f9

This patch renames the GICv3 interrupt group macros from
INT_TYPE_G0, INT_TYPE_G1S and INT_TYPE_G1NS to INTR_GROUP0,
INTR_GROUP1S and INTR_GROUP1NS respectively.

Change-Id: I40c66f589ce6234fa42205adcd91f7d6ad8f33d4

This patch adds a driver for ARM GICv3 systems that need to run software
stacks where affinity routing is enabled across all privileged exception
levels for both security states. This driver is a partial implementation
of the ARM Generic Interrupt Controller Architecture Specification, GIC
architecture version 3.0 and version 4.0 (ARM IHI 0069A). The driver does
not cater for legacy support of interrupts and asymmetric configurations.

The existing GIC driver has been preserved unchanged. The common code for
GICv2 and GICv3 systems has been refactored into a new file,
`drivers/arm/gic/common/gic_common.c`. The corresponding header is in
`include/drivers/arm/gic_common.h`.

The driver interface is implemented in `drivers/arm/gic/v3/gicv3_main.c`.
The corresponding header is in `include/drivers/arm/gicv3.h`. Helper
functions are implemented in `drivers/arm/gic/v3/arm_gicv3_helpers.c`
and are accessible through the `drivers/arm/gic/v3/gicv3_private.h`
header.

Change-Id: I8c3c834a1d049d05b776b4dcb76b18ccb927444a