staging: dgnc: fix whitespace before return

Checkpatch emits CHECK: Blank lines aren't necessary before a close
brace '}'. Previous attempts were made to make uniform the error
handling in dgnc but improvements are still possible.

Undo whitespace changes that should not have been made :(. Make return
statement placement uniform throughout dgnc. Fix checkpatch
CHECK. Make whitespace changes only.

Signed-off-by: Tobin C. Harding <me@tobin.cc>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>