Add SMALL_DISK check to pseudo

This is needed if the root dir or the out/ dir is on an SSD disk.
Device specific generated files are ~10GB (each).
Our full current lunch table generates ~300GB.
SSDs are not _that_ big yet.

Change-Id: I88c5d0746a61ad1aa1372700bb7c717e088ac2a8
Signed-off-by: Gergely Szell (sethyx) <szell@hu.ibm.com>