rtlwifi: Increase the RX queue length for USB drivers

commit dc6405712268fe514d3dd89aa936c4397b0871b9 upstream.

The current number of RX buffers queued is 32, which is too small under
heavy load. That number is doubled.

Signed-off-by: Larry Finger <Larry.Finger@lwfinger.net>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>