MLK-21150-1 drm/bridge: sec-dsim: change uint64_t clk fields to uint32_t

Change the 'bit_clk' and 'pix_clk' fields of struct sec_mipi_dsim
and the 'bit_clk' field of struct dsim_pll_pms from 'uint64_t' type
to 'uint32_t' type, since first, these two fields are in KHz unit,
and so 32 bit unsigned integer is enough to hold the data values,
and second, use 32 bit integer can simplify related clocks compute.

Signed-off-by: Fancy Fang <chen.fang@nxp.com>