mmc: sdio: Check the return value of sdio_enable_4bit_bus

Since we could move card->host->caps & MMC_CAP_4_BIT_DATA
ahead of mmc_sdio_init_uhs_card, in mmc_host_uhs(). So there
we could save this bit to check that. Also, if the process of
sdio_enable_4bit_bus goes wrong, we should bails out early.

Signed-off-by: Shawn Lin <shawn.lin@rock-chips.com>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>