Since the new ASID code in b5466f87
("ARM: mm: remove IPI broadcasting on ASID rollover") was changed to
use 64bit operations it has broken the BE operation due to an issue
with the MM code accessing sub-fields of mm->context.id.

When running in BE mode we see the values in mm->context.id are stored
with the highest value first, so the LDR in the arch/arm/mm/proc-macros.S
reads the wrong part of this field. To resolve this, change the LDR in
the mmid macro to load from +4.
Acked-by: NWill Deacon <will.deacon@arm.com>
Signed-off-by: NBen Dooks <ben.dooks@codethink.co.uk>
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>