Fix cgroup hugetlb size prefix for kB

Use the exported list from runc that uses "KB" and not "kB".

This issue breaks kubelet on AArch64 (arm 64).

var HugePageSizeUnitList = []string{"B", "KB", "MB", "GB", "TB", "PB"}

The hugetlb cgroup control files (introduced here in 2012:
https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=abb8206cb0773)
use "KB" and not "kB"
(https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/mm/hugetlb_cgroup.c?h=v5.0#n349).

The behavior in the kernel has not changed since the introduction, and
the current code using "kB" will therefore fail on devices with huge
pages smaller than 1MiB. This is the case for AArch64.

As seen from the code in "mem_fmt" inside hugetlb_cgroup.c, only "KB",
"MB" and "GB" are used, so the others may be removed as well.

Here is a real world example of the files inside the
"/sys/kernel/mm/hugepages/" directory:
- "hugepages-64kB"
- "hugepages-2048kB"
- "hugepages-32768kB"
- "hugepages-1048576kB"

And the corresponding cgroup files:
- "hugetlb.64KB._____"
- "hugetlb.2MB._____"
- "hugetlb.32MB._____"
- "hugetlb.1GB._____"

Signed-off-by: Odin Ugedal <odin@ugedal.com>

pkg/kubelet/cm/cgroup_manager_linux.go

@@ -49,10 +49,6 @@ const (
 	systemdSuffix string = ".slice"
 )
 
-// hugePageSizeList is useful for converting to the hugetlb canonical unit
-// which is what is expected when interacting with libcontainer
-var hugePageSizeList = []string{"B", "kB", "MB", "GB", "TB", "PB"}
-
 var RootCgroupName = CgroupName([]string{})
 
 // NewCgroupName composes a new cgroup name.
@@ -388,7 +384,7 @@ func (m *cgroupManagerImpl) toResources(resourceConfig *ResourceConfig) *libcont
 	// for each page size enumerated, set that value
 	pageSizes := sets.NewString()
 	for pageSize, limit := range resourceConfig.HugePageLimit {
-		sizeString := units.CustomSize("%g%s", float64(pageSize), 1024.0, hugePageSizeList)
+		sizeString := units.CustomSize("%g%s", float64(pageSize), 1024.0, libcontainercgroups.HugePageSizeUnitList)
 		resources.HugetlbLimit = append(resources.HugetlbLimit, &libcontainerconfigs.HugepageLimit{
 			Pagesize: sizeString,
 			Limit:    uint64(limit),