Description: xen/events: replace evtchn_rwlock with RCU
References:
 https://xenbits.xen.org/xsa/advisory-441.html
Notes:
 carnil> For 6.5.y fixed as well in 6.5.7.
Bugs:
upstream: released (6.6-rc6) [87797fad6cce28ec9be3c13f031776ff4f104cfc]
6.1-upstream-stable: released (6.1.57) [a4cc925e2e12c3bbffb0860acdb9f9c1abde47dd]
5.10-upstream-stable: released (5.10.198) [660627c71bc1098aa94e5f208f14748b105b73bc]
4.19-upstream-stable: released (4.19.296) [3fdf2be9089b5096a28e76376656c60ce410ac4a]
sid: released (6.5.8-1)
6.1-bookworm-security: released (6.1.64-1)
5.10-bullseye-security: released (5.10.205-1)
4.19-buster-security: released (4.19.304-1)