After the null check on md the code jumped to cmd_done, which then
will dereference md in mmc_blk_put. This patch avoids the possible
null pointer dereference in that case.
Signed-off-by: NPhilippe De Swert <philippedeswert@gmail.com>
Reviewed-by: NNamjae Jeon <linkinjeon@gmail.com>
Signed-off-by: NChris Ball <cjb@laptop.org>