arm64: Add assembly helpers for MIDR range check

Add a helper to check the MIDR of the running CPU against a given
MODEL and a range of revision and variants (just like we do in
is_affected_midr_range()). This will be useful for early checks
for MIDR to detect CPU errata.

Change-Id: I8cee3c92d2903d401d0b4235312904b706b38f7f
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Will Deacon <will.deacon@arm.com>
Cc: Marc Zyngier <marc.zyngier@arm.com>
Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Patch-mainline: linux-arm-kernel @ 01/16/2018, 10:23
[kyan@codeaurora.org: resolve trivial merge conflicts]
Signed-off-by: Kyle Yan <kyan@codeaurora.org>