If an IRQ can be requested on the card detected GPIO, use it instead of
polling.
Acked-by: NLinus Walleij <linus.walleij@stericsson.com>
Signed-off-by: NRabin Vincent <rabin.vincent@stericsson.com>
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>