Staging: dgap: Remove unnecessary variable.

This patch removes unnecessary variable in file dgap.c
using Coccinelle. Semantic patch for this is as follows:

@@
expression ret;
identifier f;
@@

-ret =
+return
     f(...);
-return ret;

Also removed the unneeded variable manually.

Signed-off-by: Ankita Patil <patil.ankita.r@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>