[ARM] sa1111: avoid using hardcoded IRQ numbers for PCMCIA driver

The IRQs for card detect and status change are currently hardcoded in
SA1111 PCMCIA driver, which can be actually obtained from the .irq[]
from 'struct sa1111_dev' to keep it generic.

Signed-off-by: Eric Miao <eric.y.miao@gmail.com>