mfd: wm5110: Remove non-existant interrupts

The DCS_DAC_DONE and DCS_HP_DONE interrupts do not exist on the wm5110
version of the IP. This patch removes them from the regmap IRQ
structure.

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