lmkd: Handle workingset_refault vmstat field change in 5.9 kernel am: dc60f9717b

Original change: https://android-review.googlesource.com/c/platform/system/memory/lmkd/+/1528739

MUST ONLY BE SUBMITTED BY AUTOMERGER

Change-Id: Ic3a3a5292dcacca866c9a1ef973e644cc00f4aba