clk: zynqmp: Limit bestdiv with maxdiv

Clock divider value should not be greater than maximum divider value.
So use minimum of best divider or maximum divider value.

Signed-off-by: Rajan Vaja <rajan.vaja@xilinx.com>
Signed-off-by: Jolly Shah <jolly.shah@xilinx.com>
Link: https://lkml.kernel.org/r/1583185843-20707-2-git-send-email-jolly.shah@xilinx.com


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