arch-arm: Make load_addr_mask=0 for ArmFsLinux only

arch-arm: Make load_addr_mask=0 for ArmFsLinux only

This is restoring the situaton pre:

https://gem5-review.googlesource.com/c/public/gem5/+/26466

Where load_addr_mask was set to 0 (forcing the loader to discard
the kernel entry point) for LinuxArmSystem only.

With this patch the masking is done for ArmFsLinux workloads
only and it is using the default 0xffffffffffffffff (no masking)
for common ArmFsWorkload

Change-Id: I68970edcac61ad0de79433ffd84fef580a94b480
Signed-off-by: Giacomo Travaglini <giacomo.travaglini@arm.com>
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/27024
Tested-by: Gem5 Cloud Project GCB service account <345032938727@cloudbuild.gserviceaccount.com>
Tested-by: kokoro <noreply+kokoro@google.com>
Reviewed-by: Gabe Black <gabeblack@google.com>