arm/edk2-firmware: apply VLA fix to all edk2 builds

sbsa-acs was fixed to solve the VLA compiler error with GCC 11, but the
problem is in EDK2 and not specific to sbsa-acs.

Apply the patch in edk2-firmware.inc so that all recipes get the fix.

Change-Id: I56b07fa0610d47bd89c1ce37cfac1205a90a4083
Signed-off-by: Ross Burton <ross.burton@arm.com>