arm: u8500_hotplug: since i am not changing the tunables as often, optimise it

Change-Id: Ic991959abfe8ca0685acae674d2c19664c90d6f7
fs/dcache.c: adaptive vfs_cache_pressure on suspend / resume

low vfs_cache pressure values save battery while idle, while
a low value also causes stutter with longer up times.

Change-Id: I81304d6588dee25b0f30520eb2349536c2f1dd9a