The Generic Timer is an optional extension to an ARMv7-A implementation.
The generic delay timer can be used from any architecture supported by
the Trusted Firmware. In ARMv7 it is needed to check that this feature
is present. In ARMv8 it is always present.

Change-Id: Ib7e8ec13ffbb2f64445d4ee48ed00f26e34b79b7
Signed-off-by: Antonio Nino Diaz <antonio.ninodiaz@arm.com>

ARMv8.2-TTCNP is mandatory from ARMv8.2 onwards, but it can be implemented
in CPUs that don't implement all mandatory 8.2 features (and so have to
claim to be a lower version).

This patch removes usage of the ARM_ARCH_AT_LEAST() macro and uses system
ID registers to detect whether it is needed to set the bit or not.

Change-Id: I7bcbf0c7c937590dfc2ca668cfd9267c50f7d52c
Signed-off-by: Antonio Nino Diaz <antonio.ninodiaz@arm.com>