arch-arm: Fix TarmacParser handling of 64bit LD/ST

arch-arm: Fix TarmacParser handling of 64bit LD/ST

The TarmacParser was assuming 32 bit accesses only.
This was creating a mismatch when parsing a trace with 64 bit
accesses.

E.g.

In

clk IT (18) 002001f4 f8008441 O EL3h_s : STR      x1,[x2],#8
clk MW8 00201008:000000201008 00000000_40000401

Only the 32 MSBs were checked (00000000)

Change-Id: I51e803b53efe953edcd9378f6c9481c04932331e
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/public/gem5/+/21562
Reviewed-by: Ciro Santilli <ciro.santilli@arm.com>
Tested-by: kokoro <noreply+kokoro@google.com>