clk: nxp: lpc32xx: convert from round_rate() to determine_rate()

The round_rate() clk ops is deprecated, so migrate this driver from
round_rate() to determine_rate() using the Coccinelle semantic patch
on the cover letter of this series.

Note that the changes involving LPC32XX_DEFINE_PLL_OPS were done
by hand.

Signed-off-by: Brian Masney <bmasney@redhat.com>