arm64: cputype: Add missing MIDR values for Cortex-A72 and Cortex-A75

Hook up MIDR values for the Cortex-A72 and Cortex-A75 CPUs, since they
will soon need MIDR matches for hardening the branch predictor.

Change-Id: Id971c30a97dafe2de803d73c9208e65d40596b86
Signed-off-by: Will Deacon <will.deacon@arm.com>
Patch-mainline: linux-arm-kernel @ 01/08/18, 9:32
[ckadabi@codeaurora.org: Resolved minor conlficts]
Signed-off-by: Channagoud Kadabi <ckadabi@codeaurora.org>