MLK-13440-5 fsl_usdhc: Remove the CONFIG_SYS_FSL_ESDHC_FORCE_VSELECT

Since we have added the "vs18_enable" parameter for fixed 1.8v I/O, remove
the CONFIG_SYS_FSL_ESDHC_FORCE_VSELECT. This configuration can only work
with one MMC device. If more devices are supported, this will set 1.8v to
all controllers, so will cause problem to 3.3v devices.

Signed-off-by: Ye Li <ye.li@nxp.com>