staging: rtl8192u: fix function definitions' style in r8192U_core.c

This patch fixes the function definitions' style in order
to be uniform across the file and in compliance with the
linux kernel coding style.

Signed-off-by: Xenia Ragiadakou <burzalodowa@gmail.com>
Reviewed-by: Dan <Carpenter&lt;dan.carpenter@oracle.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>