arm64: kernel: add MPIDR_EL1 accessors macros

In order to simplify access to different affinity levels within the
MPIDR_EL1 register values, this patch implements some preprocessor
macros that allow to retrieve the MPIDR_EL1 affinity level value according
to the level passed as input parameter.

Change-Id: I1ac939e3ca3c55a067c3211b3df3f410da80c538
Reviewed-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Git-commit: b058450f38c337d12a6d1a1bcaa8610859055e2e
Git-repo: Git-Repo: git://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git


Signed-off-by: Abhimanyu Kapur <abhimany@codeaurora.org>