power: as3722: fix ldo_get/set_enable for ldo index bigger than 7

power: as3722: fix ldo_get/set_enable for ldo index bigger than 7

Fix ldo_get_enable() and ldo_set_enable() functions for LDOs with an
index > 7. Turns out there are actually two separate AS3722_LDO_CONTROL
registers AS3722_LDO_CONTROL0 and AS3722_LDO_CONTROL1. Actually make use
of both. While at it also actually use the enable parameter of the
ldo_set_enable() function which now truly allows disabling as opposed to
only enabling LDOs.

Signed-off-by: Marcel Ziswiler <marcel.ziswiler@toradex.com>
Signed-off-by: Tom Warren <twarren@nvidia.com>