staging: rtl8712: r8712_free_drv_sw(): Change return type

Change return type of r8712_free_drv_sw from u8 to void and remove its
return statement as it always returns the same value (_SUCCESS) and even
this value is never stored, checked or otherwise used.

Signed-off-by: Nishka Dasgupta <nishkadg.linux@gmail.com>
Link: https://lore.kernel.org/r/20190808064012.12661-8-nishkadg.linux@gmail.com


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