video: rockchip: dw_mipi_dsi: Fix best_rate calculation

pllref_clk is unused after being retrieved. fin needs to be set
to dsi->ref clock's rate for the following calculation to work.
Otherwise fin is undefined, and calculation return bogus number
based on undefined variable.

Signed-off-by: Ondrej Jirman <megi@xff.cz>
1 file changed