msm: mmc: Remove "pio_irq" resource

On some targets, MCI_IRQ_MASK1 is not routed to the MSM in which
case only "cmd_irq" must be used even for PIO. With this change,
all the targets will use only "cmd_irq" for both CMD and PIO.

Signed-off-by: Sahitya Tummala <stummala@codeaurora.org>
Signed-off-by: David Brown <davidb@codeaurora.org>
Signed-off-by: Chris Ball <cjb@laptop.org>