Pull xen fixes from Juergen Gross:
"Two fix series and a single cleanup:
- a small cleanup patch to remove unneeded symbol exports
- a series to cleanup Xen grant handling (avoiding allocations in
some cases, and using common defines for "invalid" values)
- a series to address a race issue in Xen event channel handling"
* tag 'for-linus-5.12b-rc3-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/xen/tip:
Xen/gntdev: don't needlessly use kvcalloc()
Xen/gnttab: introduce common INVALID_GRANT_{HANDLE,REF}
Xen/gntdev: don't needlessly allocate k{,un}map_ops[]
Xen: drop exports of {set,clear}_foreign_p2m_mapping()
xen/events: avoid handling the same event on two cpus at the same time
xen/events: don't unmask an event channel when an eoi is pending
xen/events: reset affinity of 2-level event when tearing it down