mmc: core: Check for NULL pointer access in ioctl

Added checks to check if card is NULL before accessing it.

CRs-Fixed: 548450
Change-Id: Idc005b8420a78b3566164102fbeaa243a8e73c7c
Signed-off-by: Asutosh Das <asutoshd@codeaurora.org>
[subhashj@codeaurora.org: fixed trivial merge conflicts]
Signed-off-by: Subhash Jadavani <subhashj@codeaurora.org>
[xiaonian@codeaurora.org: fix trivial merge conflict]
Signed-off-by: Xiaonian Wang <xiaonian@codeaurora.org>
2 files changed