arch-arm: Fix masking in CPACR_EL1

Some bits in CPACR_EL1 are RES0 but not RAZ/WI. For instance, bit
CPACR_EL1[31] is RES0 but should be made stateful, since it allows
programing of CPACR.ASEDIS. Therefore the masking of CPACR_EL1
is removed.

Change-Id: If1fa3fa1e06bc38495b8afce2c635f3ddf76ce32
Reviewed-by: Andreas Sandberg <andreas.sandberg@arm.com>
Reviewed-on: https://gem5-review.googlesource.com/10046
Maintainer: Andreas Sandberg <andreas.sandberg@arm.com>
1 file changed