soc/fsl/qe: round brg_freq to 1kHz granularity
Because of integer computation rounding in u-boot (that sets the QE
brg-frequency DTS prop), the clk value is
99999999 Hz even though it is
100 MHz.
When setting brg clks that are exact divisors of 100 MHz, this small
differnce plays a role and can result in lower clks to be output (for
instance 20 MHz - divide by 5 - results in 16.666 MHz - divide by 6).
This patch fixes that by "forcing" the brg_clk to the nearest kHz when
the difference is below 2 integer rounding errors (i.e. 4).
Signed-off-by: Valentin Longchamp <valentin.longchamp@keymile.com>
Signed-off-by: Scott Wood <oss@buserror.net>