warp7: Fix the write to the LDOGCTL PMIC register

warp7: Fix the write to the LDOGCTL PMIC register

The third parameter of the pmic_clrsetbits() function is the mask
to the register and the correct mask is 1 not 0.

Since the LDOGCTL only contains a single valid bit (bit 0),
we can use pmic_reg_write() and write 1 directly, which fixes
the problem in a simpler way and use the original pmic function
that was used prior to the DM PMIC conversion.

Fixes: 5b7fa75466a3 ("arm: imx7s-warp: Convert to DM PMIC")
Signed-off-by: Fabio Estevam <festevam@gmail.com>