ARM: add support to dump the kernel page tables

This patch allows the kernel page tables to be dumped via a debugfs file,
allowing kernel developers to check the layout of the kernel page tables
and the verify the various permissions and type settings.

Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

diff --cc arch/arm/Kconfig.debug
Simple merge

diff --cc arch/arm/include/asm/pgtable-2level.h
Simple merge

diff --cc arch/arm/include/asm/pgtable-3level.h
Simple merge

diff --cc arch/arm/mm/Makefile
Simple merge

diff --cc arch/arm/mm/dump.c
Simple merge