clk: imx: Remove CLK_SET_PARENT_GATE for DRAM mux for i.MX7D

For i.MX7D DRAM related mux clock, the clock source change should ONLY
be done done in low level asm code without accessing DRAM, and then
calling clk API to sync the HW clock status with clk tree, it should never
touch real clock source switch via clk API, so CLK_SET_PARENT_GATE flag
should NOT be added, otherwise, DRAM's clock parent will be disabled when
DRAM is active, and system will hang.

Signed-off-by: Peng Fan <peng.fan@nxp.com>
Reviewed-by: Abel Vesa <abel.vesa@linaro.org>
Link: https://lore.kernel.org/r/20240607133347.3291040-8-peng.fan@oss.nxp.com


Signed-off-by: Abel Vesa <abel.vesa@linaro.org>