omapfb: Fix coding style / remove dead line

- use __iomem type attribute where appropriate
- expand (a ? : b) to (a ? a : b)
As suggested by Russell King <linux@arm.linux.org.uk>

- remove a dead line from omapfb_main.c

Signed-off-by: Arun C <arunedarath@mistralsolutions.com>
Signed-off-by: Tony Lindgren <tony@atomide.com>
Signed-off-by: Imre Deak <imre.deak@nokia.com>