UPSTREAM: arm64: add ARMv8.2 id_aa64mmfr2 boiler plate

UPSTREAM: arm64: add ARMv8.2 id_aa64mmfr2 boiler plate

ARMv8.2 adds a new feature register id_aa64mmfr2. This patch adds the
cpu feature boiler plate used by the actual features in later patches.

Signed-off-by: James Morse <james.morse@arm.com>
Reviewed-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Bug: 30369029
Patchset: kaslr-arm64-4.4

(cherry picked from commit 406e308770a92bd33995b2e5b681e86358328bb0)
Signed-off-by: Jeff Vander Stoep <jeffv@google.com>
Change-Id: I51db326696ba1e18e9a4c667acbeb3e25e0b151e