Revert "mm: Increase number of GFP masks"

This reverts commit bc3a6450bd22fa411091c47edd776f18dcd49ab4.
Revert "lowmemorykiller: Account for highmem during kswapd reclaim"

This reverts commit 04529f5f1e045758d9e6608afee68b6a3e6b4543.