ARM: OMAP2: Move sleep.S into sleep24xx.S

ARM: OMAP2: Move sleep.S into sleep24xx.S

Some register offsets are different for 242x and 243x. This
will allow compiling sleep code for both chips into the same
kernel. Pass the addresses for SDRC_DDLA_CTRL and SDRC_POWER to the
omap24xx_cpu_suspend instead of loading the values since the only.

Also fix a bug to call omap2_sram_suspend with the value of SDRC_DLLA_CTRL
instead of the address as that's what omap24xx_cpu_suspend expects to
determine between DDR and SDR. This bug has not been noticed as
the boards seem to have DDR instead of SDR.

Note that some PM patches are still missing. The PM patches will
be added later on once the base files are in sync with linux-omap
tree.

Signed-off-by: Tony Lindgren <tony@atomide.com>