staging:rtl8192u: Remove typedef of struct cmpk_txfb_t - Style

Remove the typedef of the structure cmpk_txfb_t. This clears the
checkpatch issue with defining new types.

Additionally the type is renamed from cmpk_txfb_t to cmd_pkt_tx_feedback
removing the '_t' as the typedef has been removed.

These changes are purely coding style in nature and should have no
impact on runtime code execution.

Signed-off-by: John Whitmore <johnfwhitmore@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>