USB: serial: add support Infineon modem USB flashloader driver

If you want to download Infineon modem via USB, this Infineon USB
flashloader driver is required.

Signed-off-by: Wei Shuai <cpuwolf@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
diff --git a/drivers/usb/serial/Kconfig b/drivers/usb/serial/Kconfig
index 1d55762..8c3a42e 100644
--- a/drivers/usb/serial/Kconfig
+++ b/drivers/usb/serial/Kconfig
@@ -710,6 +710,16 @@
 	  To compile this driver as a module, choose M here: the
 	  module will be called quatech-serial.
 
+config USB_SERIAL_FLASHLOADER
+	tristate "Infineon Modem Flashloader USB interface driver"
+	help
+	  Say Y here if you want to download Infineon Modem
+	  via USB Flashloader serial driver.
+
+	  To compile this driver as a module, choose M here: the
+	  module will be called flashloader.
+
+
 config USB_SERIAL_DEBUG
 	tristate "USB Debugging Device"
 	help