arch-arm: CPTR_EL3.TCPAC traps EL2 accesses to CPACR_EL1

arch-arm: CPTR_EL3.TCPAC traps EL2 accesses to CPACR_EL1

According to the arm arm, CPTR_EL3.TCPAC traps EL2 accesses to the
CPTR_EL2 or HCPTR, and EL2 and EL1 accesses to the CPACR_EL1 or CPACR,
are trapped to EL3, unless they are trapped by CPTR_EL2.TCPAC.

Change-Id: I637be35b29db39f044dda0c6cc4fe986c9620371
Signed-off-by: Giacomo Travaglini <giacomo.travaglini@arm.com>
Reviewed-by: Andreas Sandberg <andreas.sandberg@arm.com>
Reviewed-on: https://gem5-review.googlesource.com/c/13775
Maintainer: Andreas Sandberg <andreas.sandberg@arm.com>