lowmemorykiller: don't compact memory when killing processes

No improvements were observed.

------
Revert "drivers: staging: android: lmk compile fixup"

This reverts commit 9661f49b9073c79a3d498c39fb87ee156c14dacf.

------
Revert "lowmemorykiller: Use asynchronous compaction"

This reverts commit 81c8e070fd0b93738cc34b00ee85d16b924955f9.

------
Revert "lowmemorykiller: Compact memory when killing processes"

This reverts commit 677bee99c66f9a19be9c43095882cc271cc47bc4.
gp2a: P_dev.c: remove poll_delay

It's simply not used.
gp2a: remove no more needed code

These lines are the leftovers of a previous code cleanup.
gp2a: fix sysfs interface return values