drivers: media: Fix -Wpointer-to-int-cast.

drivers/media/platform/msm/cvp/hfi_response_handler.c:507:36: warning: cast to smaller integer type 'unsigned int' from 'void *' [-Wvoid-pointer-to-int-cast]
        inst = cvp_get_inst_from_id(core, (unsigned int)session_id);
                                          ^~~~~~~~~~~~~~~~~~~~~~~~

Change-Id: Iadb69f5ba617ce2c7410475bcd9bc024e3a40017