Revert "Revert "vold: allow override of MAX_PARTITIONS for devices with > 4 partitions""

This reverts commit 59dcfbbc3ac8f3a43b048bbe20181b095a661253.

Conflicts:
	DirectVolume.h

Change-Id: Id56d585f10b742ffa0113f4ee6b2e69f8da84dce
Merge remote-tracking branch 'cm/cm-10.2' into HEAD

Conflicts:
	Exfat.cpp
	Ntfs.cpp

Change-Id: I24a09f59dff443c930b7f5fbd0253f4c10609819