clk: imx: imx6sx: remove the SET_RATE_PARENT flag for QSPI clocks

clk: imx: imx6sx: remove the SET_RATE_PARENT flag for QSPI clocks

There is no dedicate parent clock for QSPI so SET_RATE_PARENT flag
should not be used. For instance, the default parent clock for QSPI is
pll2_bus, which is also the parent clock for quite a few modules, such
as MMDC, once GPMI NAND set clock rate for EDO5 mode can cause system
hang due to pll2_bus rate changed.

Fixes: f1541e15e38e ("clk: imx6sx: Switch to clk_hw based API")
Signed-off-by: Han Xu <han.xu@nxp.com>
Link: https://lore.kernel.org/r/20220915150959.3646702-1-han.xu@nxp.com
Tested-by: Fabio Estevam <festevam@denx.de>
Reviewed-by: Abel Vesa <abel.vesa@linaro.org>
Signed-off-by: Stephen Boyd <sboyd@kernel.org>