mmc: msm_sdcc: add warning if data timeout is zero

SDCC controller's MCI_DATA_TIMER register is programmed
with data timeout value while doing data transfer from/to
card. If this register is programmed with 0 timeout for
data transfer, controller will immediately throw the data
timeout error at the start of data transfer itself.

Programming timeout value as 0 is an error condition and
this patch adds WARN() when this condition is encountered.

Change-Id: I7fdde98857afeecd8e851d37a93917933caf24de
Signed-off-by: Subhash Jadavani <subhashj@codeaurora.org>