Staging: rtl8188eu: Remove redundant local variable

This patch removes a redundant variable "val" and adds
inline return statements. It also adds a default case
to the switch statement which returns 0 to keep the logic
intact.

It also removes a redundant variable "inx" and adds inline
return statements.

This issue is identified by the following coccinelle script.
@@
expression ret;
identifier f;
@@

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

Signed-off-by: Somya Anand <somyaanand214@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>