clk: imx: add missing MODULE_DESCRIPTION() macros

make allmodconfig && make W=1 C=1 reports:
WARNING: modpost: missing MODULE_DESCRIPTION() in drivers/clk/imx/mxc-clk.o
WARNING: modpost: missing MODULE_DESCRIPTION() in drivers/clk/imx/clk-imxrt1050.o

Add the missing invocations of the MODULE_DESCRIPTION() macro.

Signed-off-by: Jeff Johnson <quic_jjohnson@quicinc.com>
Reviewed-by: Abel Vesa <abel.vesa@linaro.org>
Link: https://lore.kernel.org/r/20240602-md-clk-imx-v1-1-5c6d240f6fab@quicinc.com


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