clk: iproc: round clock rate to the closest

Change from 'DIV_ROUND_UP' to 'DIV_ROUND_CLOSEST' when calculating the
clock divisor in the iProc ASIU clock driver to allow to get to the
closest clock rate.

Fixes: 5fe225c1 ("clk: iproc: add initial common clock support")
Signed-off-by: Lori Hikichi <lhikichi@broadcom.com>
Signed-off-by: Ray Jui <ray.jui@broadcom.com>
Link: https://lore.kernel.org/r/20200612225212.124301-1-ray.jui@broadcom.com


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