staging: rtl8192e: Remove explicit pointer cast in assignments

In this file, the values returned by rtllib_priv() are unnecessarily cast
into a pointer type in some assignment statements. Remove the cast as it
is unneeded.

Signed-off-by: Janani Ravichandran <janani.rvchndrn@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>