mmc: ftsdc010: make command timeout 250 ms as in the comment

Get rid of discrepancy beween comment /* 250 ms */ and code
which shifts by 4 thus dividing by 16.
So change code to shift by 2 and make the timeout value 250 ms.

Signed-off-by: Sergei Antonov <saproj@gmail.com>
Reviewed-by: Rick Chen <rick@andestech.com>
Reviewed-by: Jaehoon Chung <jh80.chung@samsung.com>