staging: atomisp: off by one in atomisp_acc_load_extensions()

We should be doing i-- on all error paths but we don't if the loop
finishes successfully.  I've re-arranged this so that we don't read
beyond the end of acc_flag_to_pipe[] array.

Fixes: a49d2536 ("staging/atomisp: Add support for the Intel IPU v2")
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>