mmc: sh_mmcif: force to fail CMD52 immediately

mmc_rescan() sends CMD52 (SD_IO_RW_DIRECT) to reset SDIO card during
card detection. CMD52 should be ignored by SD/eMMC cards, but we can
also abort it in the driver immediately, since MMCIF doesn't support
SDIO cards anyway.

Signed-off-by: Teppei Kamijou <teppei.kamijou.yb@renesas.com>
Signed-off-by: Shinya Kuribayashi <shinya.kuribayashi.px@renesas.com>
Signed-off-by: Guennadi Liakhovetski <g.liakhovetski@gmx.de>
Signed-off-by: Chris Ball <cjb@laptop.org>