mfd: arizona: Only free the CTRLIF_ERR IRQ if we requested it

We only request the control interface error IRQ if we set ctrlif_error,
as such we should only free it in that situation. Otherwise we will
attempt to free an IRQ we never requested and get a warning from the IRQ
core.

This patch moves the ctrlif_error variable into the arizona structure
and checks it in all cases we free the control interface error IRQ.

Signed-off-by: Charles Keepax <ckeepax@opensource.wolfsonmicro.com>
Signed-off-by: Lee Jones <lee.jones@linaro.org>