clk: starfive: jh7100: Handle audio_div clock properly

It turns out the audio_div clock is a fractional divider where the
lowest byte of the ctrl register is the integer part of the divider and
the 2nd byte is the number of 100th added to the divider.

The children of this clock is used by the audio peripherals for their
sample rate clock, so round to the closest possible rate rather than
always rounding down like regular dividers.

Fixes: 4210be66 ("clk: starfive: Add JH7100 clock generator driver")
Signed-off-by: Emil Renner Berthing <kernel@esmil.dk>
Link: https://lore.kernel.org/r/20220126173953.1016706-3-kernel@esmil.dk


Signed-off-by: Stephen Boyd <sboyd@kernel.org>