This patch adds the following definitions relevant to the PMSA:

Add SCTLR bit 17, (CR_BR - Background Region bit) to the list of CR_*
bitfields. This bit determines whether to use the architecturally defined
memory map

Add the MPUIR to the available registers when using read_cpuid macro. The
MPUIR is the MPU type register.
Signed-off-by: NJonathan Austin <jonathan.austin@arm.com>
Reviewed-by: NWill Deacon <will.deacon@arm.com>
CC:"Uwe Kleine-König" <u.kleine-koenig@pengutronix.de>