uboot-imx

ARM: hisilicon: hikey: do not rely on random stack value

If CONFIG_MMC_DW is not defined the return value of
init_dwmmc should not rely on a random stack value.

Instead indicate that no error occured.

The problem was indicated by cppcheck.

Signed-off-by: Heinrich Schuchardt <xypron.glpk@gmx.de>