regulator: rtq6752: fix reg reset behavior

Reg will be reset in below two conditions.
1. 'Enable' pin from H to L.
2. Both PAVDD and NAVDD are all disabled.

And 'Enable' pin also control i2c communication capability.

This patch is to Seperate the if condition in enable/disable callback for
reg cache manipulation.

Signed-off-by: ChiYuan Huang <cy_huang@richtek.com>
Link: https://lore.kernel.org/r/1626407746-23156-1-git-send-email-u0084500@gmail.com


Signed-off-by: Mark Brown <broonie@kernel.org>