Revert "regulator: onsemi-ncp6335d: add support for tlmm spare register control"

TLMM_SPARE register will be controlled at bootloader. Remove the
TLMM_SPARE register access in onsemi-ncp6335d regulator driver.

This reverts commit e61b7c50.

Change-Id: I73319ff47c6656e2c042736ad507c73ddb9065c8
Signed-off-by: Fenglin Wu <fenglinw@codeaurora.org>