UPSTREAM: ARM: fix uaccess_with_memcpy() with SW_DOMAIN_PAN

The uaccess_with_memcpy() code is currently incompatible with the SW
PAN code: it takes locks within the region that we've changed the DACR,
potentially sleeping as a result.  As we do not save and restore the
DACR across co-operative sleep events, can lead to an incorrect DACR
value later in this code path.

Reported-by: Peter Rosin <peda@axentia.se>
Tested-by: Peter Rosin <peda@axentia.se>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

Change-Id: Iaa6ef00ad4d084eb24b9941a97ffe201635de003
(cherry picked from commit c014953d)
Signed-off-by: Sami Tolvanen <samitolvanen@google.com>