[TEMP] rss: Hardcode ICBC_RESET_VALUE

Due to a FVP bug, this value is currently hardcoded in the FVP to an
incorrect value. Temporarily override that here to allow the boot to
continue.

Note, this sets a default value in the RSS integrity checker. Without
this the integrity checker fails to verify when loading data into the
OTP, leading the RSS boot to fail.

Signed-off-by: Jackson Cooper-Driver <jackson.cooper-driver@arm.com>