soc: xilinx: vcu: remove calculation of PLL configuration

soc: xilinx: vcu: remove calculation of PLL configuration

As the consumers are now responsible for setting the clock rate via
clock framework, the clock rate is now calculated using round_rate and
the driver does not need to calculate the clock rate beforehand.

Remove the code that calculates the PLL configuration.

Signed-off-by: Michael Tretter <m.tretter@pengutronix.de>
Acked-by: Michal Simek <michal.simek@xilinx.com>
Link: https://lore.kernel.org/r/20210121071659.1226489-12-m.tretter@pengutronix.de
Signed-off-by: Stephen Boyd <sboyd@kernel.org>