USB: io_ti: check firmware version before updating

If we can't read the firmware for a device from the disk, and yet the
device already has a valid firmware image in it, we don't want to
replace the firmware with something invalid.  So check the version
number to be less than the current one to verify this is the correct
thing to do.
Reported-by: Chris Beauchamp <chris@chillibean.tv>
Tested-by: Chris Beauchamp <chris@chillibean.tv>
Cc: Alan Stern <stern@rowland.harvard.edu>
Cc: stable <stable@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

drivers/usb/serial/io_ti.c

@@ -1151,7 +1151,7 @@ static int download_fw(struct edgeport_serial *serial)
 
 			/* Check if we have an old version in the I2C and
 			   update if necessary */
-			if (download_cur_ver != download_new_ver) {
+			if (download_cur_ver < download_new_ver) {
 				dbg("%s - Update I2C dld from %d.%d to %d.%d",
 				    __func__,
 				    firmware_version->Ver_Major,