spm: add config to support RESET_TO_BL31

Google's hafnium CI skips BL1/BL2 boot stages and boots BL31 directly.
This patch replicates hafnium CI's setup and it will be a base for
consolidation of both CI's in the future.

Since there is no BL2, along with other images Secure partitions are
also pre-loaded using model commands.

Change-Id: If81ae9d5b2c2abc68ff2573c4b1a23080b5789e2
Signed-off-by: Manish Pandey <manish.pandey2@arm.com>
Signed-off-by: Sandrine Bailleux <sandrine.bailleux@arm.com>
5 files changed