el3_payload: Add initial platform support for SGI-575

SGI-575 platform consists of two clusters of four Cortex-A75 CPUs
each. CPU0 of the first cluster is the primary CPU. SoC UART0 is
used for the console log.

Change-Id: I9e3c188643aa699f57bc3f51e9d15f44f84f987c
Signed-off-by: Chandni Cherukuri <chandni.cherukuri@arm.com>
3 files changed