arm64: Make !dirty ptes read-only
arm64: Make !dirty ptes read-only

The AArch64 Linux port relies on the mm code to wrprotect clean ptes.
This however is not the case with newly created ptes and
PAGE_SHARED(_EXEC) is writable but !dirty.

Signed-off-by: Catalin Marinas <15ce75b290ebaf27c3f9fd73ab848685ed3d8261@arm.com>
Cc: <4fbacc2fa0ffdbb11bf1ad6925b886ebd08dd15f@vger.kernel.org>

TeamVee-Kanas/android_kernel_samsung_kanas,TeamVee-Kanas/android_kernel_samsung_kanas,TeamVee-Kanas/android_kernel_samsung_kanas,TeamVee-Kanas/android_kernel_samsung_kanas,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,TeamVee-Kanas/android_kernel_samsung_kanas