clk: imx93: keep sys ctr clock always on

Keep sys ctr clock always on to make sure its register
can be accessed for cpuidle.

Reviewed-by: Peng Fan <peng.fan@nxp.com>
Signed-off-by: Jacky Bai <ping.bai@nxp.com>
Signed-off-by: Peng Fan <peng.fan@nxp.com>
Reviewed-by: Abel Vesa <abel.vesa@linaro.org>
Signed-off-by: Abel Vesa <abel.vesa@linaro.org>
Link: https://lore.kernel.org/r/20221028095211.2598312-7-peng.fan@oss.nxp.com