mmc: core: Port trivial fixes in mmc from earlier kernels

This is a squash of below minor fixes:

7f5e93a mmc: block: Disable clock scaling during shudown
6c432c8 mmc: core: remove shutdown handler
b93ed34 mmc: core: declare local stack arrays as const
bbefab3 mmc: core: Check for NULL pointer access in ioctl
ecb7097 mmc: core: add checks for pointers before driver shutdown.
2952df2 mmc: mmc_test: Fix possible NULL pointer dereference
aa0a814 mmc: core: Skip frequency retries for SDCC slot
8a5e147 mmc: core: Claim host while freeing card.
7ad1fc3 mmc: core: hpi in TRAN state error handling
cfad32e mmc: core: fix issue with HPI polling timeout
9151c53 mmc: core: Attribute the IO wait time properly in
			mmc_wait_for_req_done().

Change-Id: I93c8a14a5cbd3546b44dba78fb5048b4deafe110
Signed-off-by: Murali Palnati <palnatim@codeaurora.org>
Signed-off-by: Subhash Jadavani <subhashj@codeaurora.org>
Signed-off-by: Sujit Reddy Thumma <sthumma@codeaurora.org>
Signed-off-by: Eugene Yasman <eyasman@codeaurora.org>
Signed-off-by: Asutosh Das <asutoshd@codeaurora.org>
Signed-off-by: Venkat Gopalakrishnan <venkatg@codeaurora.org>
Signed-off-by: Vijay Viswanath <vviswana@codeaurora.org>
Signed-off-by: Veerabhadrarao Badiganti <vbadigan@codeaurora.org>