ARM: OMAP2+: pm33xx-core: Add platform code needed for PM

Most of the PM code needed for am335x and am437x can be moved into a
module under drivers but some core code must remain in mach-omap2 at the
moment. This includes some internal clockdomain APIs and low-level ARM
APIs which are also not exported for use by modules.

Implement a few functions that handle these low-level platform
operations can be passed to the pm33xx module through the use of
platform data.

In addition to this, to be able to share data structures between C and
the sleep33xx and sleep43xx assembly code, we can automatically generate
all of the C struct member offsets and sizes as macros by processing
pm-asm-offsets.c into assembly code and then extracting the relevant
data as is done for the generated platform asm-offsets.h files.

Finally, add amx3_common_pm_init to create a dummy platform_device for
pm33xx so that our soon to be introduced pm33xx module can probe on
am335x and am437x platforms to enable basic suspend to mem and standby
support.

Signed-off-by: Dave Gerlach <d-gerlach@ti.com>
Acked-by: Santosh Shilimkar <ssantosh@kernel.org>
Signed-off-by: Tony Lindgren <tony@atomide.com>