aarch32: Implement cpu_rev_var_hs()
aarch32: Implement cpu_rev_var_hs()

Helper function to assist with errata workaround application.

Change-Id: Idba42ca238442cc826f43444dbfa754e433a5e5e
Signed-off-by: Dimitris Papastamos <5172875e934a989df22d22726b6d9d921b91fbdd@arm.com>

lsigithub/arm-trusted-firmware_public,lsigithub/arm-trusted-firmware_public,achingupta/arm-trusted-firmware,achingupta/arm-trusted-firmware