Pull more xen updates from Juergen Gross:

 - Remove support for running as 32-bit Xen PV-guest.

   32-bit PV guests are rarely used, are lacking security fixes for
   Meltdown, and can be easily replaced by PVH mode. Another series for
   doing more cleanup will follow soon (removal of 32-bit-only pvops
   functionality).

 - Fixes and additional features for the Xen display frontend driver.

* tag 'for-linus-5.9-rc1b-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/xen/tip:
  drm/xen-front: Pass dumb buffer data offset to the backend
  xen: Sync up with the canonical protocol definition in Xen
  drm/xen-front: Add YUYV to supported formats
  drm/xen-front: Fix misused IS_ERR_OR_NULL checks
  xen/gntdev: Fix dmabuf import with non-zero sgt offset
  x86/xen: drop tests for highmem in pv code
  x86/xen: eliminate xen-asm_64.S
  x86/xen: remove 32-bit Xen PV guest support