ARM: OMAP2+: SmartReflex: introduce a busy loop condition test macro

Now that omap_test_timeout is only accessible from mach-omap2/,
introduce a similar function for SR.

This change makes the SmartReflex implementation ready for the move
to drivers/.

Signed-off-by: Jean Pihet <j-pihet@ti.com>
Signed-off-by: J Keerthy <j-keerthy@ti.com>
Reviewed-by: Kevin Hilman <khilman@ti.com>
Signed-off-by: Kevin Hilman <khilman@ti.com>