fix(rmm): add support for BRBCR_EL2 register for feat_brbe

Currently BRBE is being disabled for Realm world in EL3 by
switching the SBRBE bit in mdcr_el3 register to 0b00.
The patch removes the switching of SBRBE bits, and adds
context switch of BRBCR_EL2 register.

Change-Id: I66ca13edefc37e40fa265fd438b0b66f7d09b4bb
Signed-off-by: Sona Mathew <sonarebecca.mathew@arm.com>
4 files changed