staging:vt6656:dpc.c:Fix spaces

The following patch fixes two checks thrown by checkpatch.pl, "Spaces
preferred around '+'" and "No space is necessary after a cast"

Signed-off-by: Rithvik Patibandla <rithvikp98@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>