ARM: OMAP: Combine sleep242x.S and sleep243x.S and fix error for SDR

We can pass the addresses for SDRC_DDLA_CTRL and SDRC_POWER to the
omap24xx_cpu_suspend instead of loading the values since the only
difference between 242x and 243x is the address of these registers.

Also 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.

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