staging: r8188eu: make rtw_chk_hi_queue_cmd a void function

Both callers of rtw_chk_hi_queue_cmd do not check the return value.
Convert rtw_chk_hi_queue_cmd to a void function.

Signed-off-by: Martin Kaiser <martin@kaiser.cx>
Tested-by: Philipp Hortmann <philipp.g.hortmann@gmail.com> # Edimax N150
Link: https://lore.kernel.org/r/20230123205342.229589-14-martin@kaiser.cx


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