The eSDHC reference clocks should be provided by speed.c in arch/.
And we do not need CONFIG_FSL_ESDHC_USE_PERIPHERAL_CLK option to
select which clock to use. Because we can make the driver to select
the periperhal clock which is better (provides higher frequency)
automatically if its value is provided by speed.c.

This patch is to drop this option and make driver to select clock
automatically. Also fix peripheral clock calculation issue in
fsl_lsch2_speed.c/fsl_lsch3_speed.c.
Signed-off-by: NYangbo Lu <yangbo.lu@nxp.com>