RSE: RD-V3: allow secure accesses from AP to SRAM

Allow Secure PAS accesses from AP to SRAM as it needs to read the SPMC
manifest loaded into the SRAM from EL2_S state.

Signed-off-by: Rakshit Goyal <rakshit.goyal@arm.com>
Change-Id: Ib9518e3991a05eaa3497f869213cbe95175359a0