BACKPORT: arm64/debug: Make use of the system wide safe value

Use the system wide value of ID_AA64DFR0 to make safer decisions

Signed-off-by: Suzuki K. Poulose <suzuki.poulose@arm.com>
Tested-by: Dave Martin <Dave.Martin@arm.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>

Bug: 31432001
Change-Id: Id0d0c664a3de9399c92bf5200f42840fbd402fba
(cherry picked from commit 3085bb01b40676d946a13064483ab2819ae3b010)
Signed-off-by: Sami Tolvanen <samitolvanen@google.com>
3 files changed