Staging: iio: meter: ade7753: Merged assignment with immediately following return statement

Saved one line of code by merging the assigning and return statements
of variable ret. And thus removed variable len which was no longer useful.

This patch was done using Coccinelle script and the following semantic
patch was used:

@@
expression ret;
identifier f;
@@

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

Signed-off-by: Tina Johnson <tinajohnson.1234@gmail.com>
Acked-by: Julia Lawall <julia.lawall@lip6.fr>
Acked-by: Josh Triplett <josh@joshtriplett.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>