arm64: Do not synchronise I and D caches for special ptes

arm64: Do not synchronise I and D caches for special ptes

commit 71fdb6bf61bf0692f004f9daf5650392c0cfe300 upstream.

Special pte mappings are not intended to be executable and do not even
have an associated struct page. This patch ensures that we do not call
__sync_icache_dcache() on such ptes.

Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Reported-by: Steve Capper <Steve.Capper@arm.com>
Tested-by: Laura Abbott <lauraa@codeaurora.org>
Tested-by: Bharat Bhushan <Bharat.Bhushan@freescale.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
(cherry picked from commit b1f2bfc9d8bb42b4e5a93470e8a0974cd4c04697)
Signed-off-by: Mark Brown <broonie@linaro.org>