USB: add USB serial mos7720 driver

Add support for Moschip 7720 USB dual port usb to serial device.

This driver is originally based on the drivers/usb/io_edgeport.c driver.

Cleaned up and forward ported by me.

Cc: VijayaKumar <vijaykumar@aspirecom.net>
Cc: AjayKumar <ajay@aspirecom.net>
Cc: Gurudeva <gurudev@aspirecom.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

diff --git a/drivers/usb/serial/Kconfig b/drivers/usb/serial/Kconfig
index 5076b9d..8ca6d3f 100644
--- a/drivers/usb/serial/Kconfig
+++ b/drivers/usb/serial/Kconfig
@@ -422,6 +422,16 @@
 	  To compile this driver as a module, choose M here: the
 	  module will be called mct_u232.
 
+config USB_SERIAL_MOS7720
+	tristate "USB Moschip 7720 Single Port Serial Driver"
+	depends on USB_SERIAL
+	---help---
+	  Say Y here if you want to use a USB Serial single port adapter from
+	  Moschip Semiconductor Tech.
+
+	  To compile this driver as a module, choose M here: the
+	  module will be called mos7720.
+
 config USB_SERIAL_MOS7840
 	tristate "USB Moschip 7840/7820 USB Serial Driver"
 	depends on USB_SERIAL