USB: serial: export usb_serial_generic_chars_in_buffer

Export generic chars_in_buffer implementation so it can be used in
subdrivers in combination with checks of any hardware buffers.

Signed-off-by: Johan Hovold <jhovold@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
1 file changed