plat/arm/sgi: move bl31_platform_setup to board file

For SGI-575 and RD platforms, move bl31_platform_setup handler to
individual board files to allow the platforms to perform board specific
bl31 setup.

Change-Id: Ia44bccc0a7f40a155b33909bcb438a0909b20d42
Signed-off-by: Vijayenthiran Subramaniam <vijayenthiran.subramaniam@arm.com>
5 files changed