Rationalize UART usage among different BL stages ...

This patch changes the UART port assignment for various BL stages
so as to make it consistent on the platform ports. The BL1, BL2 and
BL3-1 now uses UART0 on the FVP port and SoC UART0 on the Juno port.
The BL3-2 uses UART2 on the FVP port and FPGA UART0 on the Juno
port.

This provides an interim fix to ARM-software/tf-issues#220 until
support is added for changing the UART port for a BL image between
cold boot and runtime.

Change-Id: Iae5faea90be3d59e41e597b34a902f93e737505a

Juno: Read primary CPU MPID from SCC GPR_1 ...

This patch removes the PRIMARY_CPU definition hardcoded in the
Juno port. Instead, the primary CPU is obtained at runtime by
reading the SCC General Purpose Register 1 (GPR_1), whose value
is copied by the SCP into shared memory during the boot process.

Change-Id: I3981daa92eb7142250712274cf7f655b219837f5

Juno: Add support for Test Secure-EL1 Payload ...

This patch implements the TSP on Juno. It executes from on-chip Trusted
SRAM.

Also, the other bootloader images (i.e. BL1 R/W, BL2 and BL3-1) have
been moved around. The reason is, although there was enough space
overall to store the TSP in SRAM, there was no contiguous free chunk
of SRAM big enough to hold it.

This patch keeps the overall memory layout (i.e. keeping BL1 R/W at
the bottom, BL2 at the top and BL3-1 in between) but moves the base
addresses of all the bootloader images in such a way that:
 - memory fragmentation is reduced enough to fit BL3-2 in;
 - new base addresses are suitable for release builds as well as debug
   ones;
 - each image has a few extra kilobytes for future growth.
   BL3-1 and BL3-2 are the images which received the biggest allocations
   since they will most probably grow the most.

This patch also adds instruction synchronization barriers around the code which
handles the timer interrupt in the TSP. This ensures that the interrupt is not
acknowledged after or EOIed before it is deactivated at the peripheral.

Change-Id: I1c5b51858700027ee283ac85d18e06863a27c72e

Juno: Implement initial platform port ...

This patch adds the initial port of the ARM Trusted Firmware on the Juno
development platform. This port does not support a BL3-2 image or any PSCI APIs
apart from PSCI_VERSION and PSCI_CPU_ON. It enables workarounds for selected
Cortex-A57 (#806969 & #813420) errata and implements the workaround for a Juno
platform errata (Defect id 831273).

Change-Id: Ib3d92df3af53820cfbb2977582ed0d7abf6ef893