This patch generalises trap checking when accessing system registers in AArch64. Depending on the accessed register, a different Exception Class (EC) and immediate value may be set. Previously this only took SIMD traps into account. Change-Id: I30717676a210c770531e39e4c6a6e1fbfdfdc583 Reviewed-by: Giacomo Travaglini <giacomo.travaglini@arm.com> Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/23765 Maintainer: Giacomo Travaglini <giacomo.travaglini@arm.com> Tested-by: kokoro <noreply+kokoro@google.com>