m7-common: don't check for valid data partition

* /data partition may be encrypted

Change-Id: Ibf5a39fb4fbb10bb23fb695f7a1a734c1119cb6d
m7: require vendor

Change-Id: I75c30efd0de4cbd57569766b05c84f43c367f3f4
Merge remote-tracking branch 'cm/cm-10.2' into HEAD