staging: dgnc_driver.c: code style fixes

Simple code style fixes:
 - "if(" -> "if ("
 - "switch(" -> "switch ("
 - move one open brace to the line of the declaration instead of
   its own line
 - remove trailing whitespace

Signed-off-by: Guillaume Morin <guillaume@morinfr.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>