Merge pull request #42263 from AkihiroSuda/move-cgroup2-out-of-experimental-20.10

[20.10 backport] Move cgroup v2 out of experimental
diff --git a/daemon/info_unix.go b/daemon/info_unix.go
index 56c9209..73d5663 100644
--- a/daemon/info_unix.go
+++ b/daemon/info_unix.go
@@ -122,9 +122,6 @@
 		if !v.CPUSet {
 			v.Warnings = append(v.Warnings, "WARNING: No cpuset support")
 		}
-		if v.CgroupVersion == "2" {
-			v.Warnings = append(v.Warnings, "WARNING: Support for cgroup v2 is experimental")
-		}
 		// TODO add fields for these options in types.Info
 		if !sysInfo.BlkioWeight && v.CgroupVersion == "2" {
 			// blkio weight is not available on cgroup v1 since kernel 5.0.