mmc: Hide mmc speed command under mmc command

The mmc speed command configuration option keeps showing up in
Kconfig directly in 'Command line interface'. Move MMC_SPEED_MODE_SET
under CMD_MMC to make it show up alongside the MMC command.

Signed-off-by: Marek Vasut <marek.vasut+renesas@mailbox.org>
Reviewed-by: Quentin Schulz <quentin.schulz@cherry.de>
Reviewed-by: Mattijs Korpershoek <mkorpershoek@baylibre.com>
1 file changed