uboot-imx

cmd: Kconfig: Make CMD_UBI select CMD_MTDPARTS

Many configs still define CMD_MTDPARTS in their non-Kconfig but
CMD_MTDPARTS has now moved to Kconfig.

Signed-off-by: Karl Beldan <karl.beldan-ext@sagemcom.com>
Reviewed-by: Tom Rini <trini@konsulko.com>