drivers/mmc/host/omap.c: use resource_size()

Signed-off-by: Chris Ball <cjb@laptop.org>
Cc: Jarkko Lavinen <jarkko.lavinen@nokia.com>
Cc: Tony Lindgren <tony@atomide.com>
Cc: <linux-mmc@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>