refactor(plat/sgi): deprecate DMC-620 RAS support

Remove DMC-620 specific code from platform RAS implementation. DMC-620
RAS support is not supported on SGI and RD platforms. The rest of the
platform specific code maintained will be reused for supporting RAS
error handling on RD-N2 and later platforms.

Signed-off-by: Omkar Anand Kulkarni <omkar.kulkarni@arm.com>
Change-Id: Ic03ae0e3298628330c5f7c25bafb0131f7b9d5b6
1 file changed