UPSTREAM: arm64: mm: Temporarily disable ARM64_SW_TTBR0_PAN

We're about to rework the way ASIDs are allocated, switch_mm is
implemented and low-level kernel entry/exit is handled, so keep the
ARM64_SW_TTBR0_PAN code out of the way whilst we do the heavy lifting.

It will be re-enabled in a subsequent patch.

Reviewed-by: Mark Rutland <mark.rutland@arm.com>
Tested-by: Laura Abbott <labbott@redhat.com>
Tested-by: Shanker Donthineni <shankerd@codeaurora.org>
Signed-off-by: Will Deacon <will.deacon@arm.com>
(cherry picked from commit 376133b7edc20f237a42e4c72415cc9e8c0a9704)
Signed-off-by: Todd Poynor <toddpoynor@google.com>

Change-Id: Iac0d096cd8eda5bc2d3cd17d7d2492d1838ad8ed
Signed-off-by: Greg Kroah-Hartman <gregkh@google.com>