util: getCgroupPidsFile produces striped path when extra : present

This commit uses `string.SplitN` instead of `string.Split`.
The path for pids.max has extra `:` symbols in it due to which
getCgroupPidsFile() splits the string into 5 tokens instead of
3 leading to loss of part of the path.
As a result, the below error is reported:
`Failed to get the PID limit, can not reconfigure: open
/sys/fs/cgroup/pids/system.slice/containerd.service/
kubepods-besteffort-pod183b9d14_aed1_4b66_a696_da0c738bc012.slice/pids.max:
no such file or directory`
SplitN takes an argument n and splits the string
accordingly which helps us to get the desired
file path.

Fixes: #2337

Co-authored-by: Yati Padia <ypadia@redhat.com>
Signed-off-by: Yati Padia <ypadia@redhat.com>
(cherry picked from commit 16ec97d8f7)

internal/util/pidlimit.go

@@ -47,7 +47,7 @@ func getCgroupPidsFile() (string, error) {
 	scanner := bufio.NewScanner(cgroup)
 	var slice string
 	for scanner.Scan() {
-		parts := strings.Split(scanner.Text(), ":")
+		parts := strings.SplitN(scanner.Text(), ":", 3)
 		if parts == nil || len(parts) < 3 {
 			continue
 		}