staging: rtl8192u: Remove typedef for struct _bandwidth_autoswitch

-Avoid typedefs for structure types to maintain kernel coding style.
-Remove typedefs bandwidth_autoswitch and *pbandwidth_autoswitch of
struct _bandwidth_autoswitch.
-Change Structure name _bandwidth_autoswitch to bandwidth_autoswitch to
maintain Linux kernel Coding Style.
-Replace occurence of bandwidth_autoswitch to struct bandwidth_autoswitch.

Signed-off-by: Bhanusree Pola <bhanusreemahesh@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>