uboot-imx

MLK-21165 imx8: Workaround LPCG HW issue

There are two LPCG HW issues reported in TKT322331. Add workaround
for them in u-boot.
1. Back to back LPCG write access must have 4x DSC cycle interval.
2. When DSC clock is gated, LPCG write access may be missed due to
   the edge detect is not see by DSC. Two writes shall be performed
   to re-enable the clock if DSC clock is gated

Signed-off-by: Ye Li <ye.li@nxp.com>
Reviewed-by: Peng Fan <peng.fan@nxp.com>
(cherry picked from commit 96186ca0048e6ae261176e5f3ebf02be09bacb08)