OMAPFB: remove silly loop in fb2display()

fb2display() has a for loop which always returns at the first iteration.
Replace the loop with a simple if.

This removes the smatch warning:

drivers/video/omap2/omapfb/omapfb.h:153 fb2display() info: loop could be
replaced with if statement.

Signed-off-by: Tomi Valkeinen <tomi.valkeinen@ti.com>