[bionic] updates to Exar USB serial driver

[Shrirang Bagul]

[SRU Justification]

[Impact]
This update adds the latest vendor release version on the Exar USB serial device.

[Fixes]
New features include:
1. Fix for RX fail after wake-up from sleep (S3/S4)
2. Removes unnecessary debug messages

Changelog:

Version 1B, 11/6/2015
Fixed Bug: The conditional logic to support kernel 3.9 was
incorrect(line 396 in xr_usb_serial_common.c).

Version 1A, 1/9/2015
This driver will work with any USB UART function in these Exar devices:
XR21V1410/1412/1414
XR21B1411
XR21B1420/1422/1424
XR22801/802/804

Exar serial devices are typically enumerated as /dev/ttyXRUSB[0-3].

[Regression Potential]
Low. This driver binds to Exar USB Serial devices on the Dell Edge 300x GW.
These updates are being carried in the linux-oem (4.15.y) kernel for more than 2 years without any regressions.

This bug is for tracking purposes only, please don't triage.

[Ubuntu Kernel Bot (ubuntu-kernel-bot)]

This bug is awaiting verification that the kernel in -proposed solves the problem. Please test the kernel and update this bug with the results. If the problem is solved, change the tag 'verification-needed-bionic' to 'verification-done-bionic'. If the problem still exists, change the tag 'verification-needed-bionic' to 'verification-failed-bionic'.

If verification is not done by 5 working days from today, this fix will be dropped from the source code, and this bug will be closed.

See https://wiki.ubuntu.com/Testing/EnableProposed for documentation how to enable and use -proposed. Thank you!