staging: rtl8192u: Remove typedef for struct _IbssParms

-Avoid typedefs for structure types to maintain kernel coding style.
-Remove typedefs IbssParms and *PIbssParms of struct _IbssParms.
-Change Structure name _IbssParms to ibss_parms to maintain Linux kernel Coding Style.
-Replace occurence of IbssParms to struct ibss_parms.

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