staging: rtl8712: r8712_xmitframe_aggr_1st(): Change return type to void

Change return type of r8712_xmitframe_aggr_1st from u8 to void as it
always returns _SUCCESS and its return value is never used.

Signed-off-by: Nishka Dasgupta <nishkadg.linux@gmail.com>
Link: https://lore.kernel.org/r/20190813044638.16348-3-nishkadg.linux@gmail.com


Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>