arm: Add support for CONFIG_ENABLE_DMM

Add a new config ENABLE_DMM that will turn on/off the DMM feature.
DMM stands for "dynamic memory management" (the ability to power
off some memory when the system is idle) and the reason this
is needed is that many customers do not want this functionality
and we want to provide a consistent and simple way of turning
this off, rather than the ad-hoc methods some have been using.

DMM currently is enabled by default on 8960.

The following configs are currently used only by DMM
and will be disabled if ENABLE_DMM is not true.

CONFIG_MEMORY_HOTPLUG
CONFIG_HOTREMOVE
CONFIG_ARCH_ENABLE_MEMORY_HOTPLUG
CONFIG_ARCH_ENABLE_MEMORY_HOTREMOVE
CONFIG_MIGRATION
CONFIG_ARCH_MEMORY_PROBE
CONFIG_ARCH_MEMORY_REMOVE

CRs-Fixed: 344176
Change-Id: I1f1fa8a8882136a38f0abd01b0f5cb59c9a25152
Signed-off-by: Jack Cheung <jackc@codeaurora.org>
Signed-off-by: Larry Bassel <lbassel@codeaurora.org>
(cherry picked from commit b8d6102e021946973b20f4c2646e24c256eaab32)

Conflicts:

	arch/arm/Kconfig
	arch/arm/mach-msm/Kconfig
	arch/arm/mach-msm/board-8930.c
	arch/arm/mach-msm/board-8960.c
	arch/arm/mach-msm/memory_topology.c