ARM: pm: omap3: move saving of the auxiliary control registers to C

Move the saving of the auxiliary control registers into C; there's
no need for this to be in assembly code.  This results in less
assembly code to deal with in OMAP.

Kevin tested full-chip retention and off on 3430/n900, 3530/Overo and
3630/Zoom3.

Tested-by: Kevin Hilman <khilman@ti.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>