Staging: bcm: Remove typedef for stUserThreadReq and call directly.

This patch removes typedef for stUserThreadReq,
and changes the name of the struct to bcm_user_thread_req.
In addition, any calls to typedefs USER_THREAD_REQ, or
*PUSER_THREAD_REQ are changed to call the struct directly.

Signed-off-by: Kevin McKinney <klmckinney1@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>