ARMv8R/M architecture defines new memory protection scheme - PMSAv8
which is not compatible with PMSAv7.

Key differences to PMSAv7 are:
 - Region geometry is defined by base and limit addresses
 - Addresses need to be either 32 or 64 byte aligned
 - No region priority due to overlapping regions are not allowed
 - It is unified, i.e. no distinction between data/instruction regions
 - Memory attributes are controlled via MAIR

This patch implements support for PMSAv8 MPU defined by ARMv8R/M
architecture.
Signed-off-by: NVladimir Murzin <vladimir.murzin@arm.com>
Signed-off-by: NRussell King <rmk+kernel@armlinux.org.uk>