uboot-imx

mmc: sdhci: return error when failed add_sdhci().

If failed the add_host(), it is reasonable that return value of
add_sdhci().

Signed-off-by: Jaehoon Chung <jh80.chung@samsung.com>
Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com>
Signed-off-by: Andy Fleming <afleming@freescale.com>