Staging: dgnc: Merge lines and remove unused variable for immediate return

This patch merges two lines in a single line if immediate
return is found. It also removes unnecessory variable rc
as it is no longer needed.

This is done using Coccinelle. Semantic patch used for this
is as follows:

@@
type T;
identifier i;
identifier f;
constant C;
@@
- T i;
  ...when != i
     when strict
(
  return -C;
|
- i =
+ return
     f(...);
- return i;
)

Signed-off-by: Vaishali Thakkar <vthakkar1994@gmail.com>
Reviewed-by: Julia Lawall <julia.lawall@lip6.fr>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>