omap4: Fix build break by moving omap_smc1 into a separate .S

This patch moves omap_smc1 function to a seperate omap44xx-smc.S file
and sets compile flags as -Wa,-march=armv7-a.

This fix was suggested by Tony Lindgren <tony@atomide.com>

Signed-off-by: Santosh Shilimkar <santosh.shilimkar@ti.com>
[tony@atomide.com: otherwise multi-omap build with V6 and V7 breaks]
Signed-off-by: Tony Lindgren <tony@atomide.com>