mfd: qcom-pm8008: Remove workaround for a regmap-irq quirk

Remove pm8008_init(), which according to the comments exists only
as a workaround for regmap-irq's odd treatment of type registers.
This workaround shouldn't be needed anymore because this driver
uses config registers, which are always programmed by regmap-irq
no matter what the initial register state is.

Signed-off-by: Aidan MacDonald <aidanmacdonald.0x0@gmail.com>
Signed-off-by: Lee Jones <lee@kernel.org>
Link: https://lore.kernel.org/r/20230216222214.138671-5-aidanmacdonald.0x0@gmail.com