ARM: mm: Transparent huge page support for LPAE systems.

The patch adds support for THP (transparent huge pages) to LPAE
systems. When this feature is enabled, the kernel tries to map
anonymous pages as 2MB sections where possible.

Change-Id: Ib042437c9e526e5fb8adda016940d647b62c4fb6
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
[steve.capper@linaro.org: symbolic constants used, value of
PMD_SECT_SPLITTING adjusted, tlbflush.h included in pgtable.h,
added PROT_NONE support.]
Signed-off-by: Steve Capper <steve.capper@linaro.org>
Reviewed-by: Will Deacon <will.deacon@arm.com>
Git-commit: 8d962507007357d6fbbcbdd1647faa389a9aed6d
Git-repo: git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git


[mitchelh@codeaurora.org: minor context differences]
Signed-off-by: Mitchel Humpherys <mitchelh@codeaurora.org>