ARM: OMAP2+: Remove unnecessary ifdef around __omap2_set_globals

The function __omap2_set_globals() can be common across all
platforms/architectures, even in case of omap4, internally it
calls same set of functions as in __omap2_set_globals() function
(except for sdrc).
This patch adds new config flag SOC_HAS_OMAP2_SDRC to handle sdrc,
so that we can reuse same function across omap2/3/4...

Signed-off-by: Vaibhav Hiremath <hvaibhav@ti.com>
Cc: Kevin Hilman <khilman@ti.com>
Cc: Paul Walmsley <paul@pwsan.com>
Signed-off-by: Tony Lindgren <tony@atomide.com>