Regmap will refuse to read a register which is not marked as readable,
this has highlighted a number of controls in this driver which are not
marked as readable/missing defaults.
This patch corrects the situation, by adding the missing
readables/defaults.
Signed-off-by: Charles Keepax <ckeepax@opensource.wolfsonmicro.com> Signed-off-by: Lee Jones <lee.jones@linaro.org>