media: staging: atomisp: fix bounds checking in mt9m114_s_exposure_selection()

These clamp_t() calls are no-ops because we don't save the results.  It
leads to an array out of bounds bug.

Fixes: a49d2536 ("staging/atomisp: Add support for the Intel IPU v2")

Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>