m7-common: handle all init scripts in m7-common

All GSM variants share the same partition layout, so have them share the
same from m7-common.

Change-Id: Ibb1ae24ad0231b6a99dd9a056dbb6896076d556d
m7-common: handle recovery fstab in m7-common

Change-Id: I20a77267291cf8edc5506b25814bf24c2af3c863
m7-common: mount debugfs for systrace

Change-Id: I1fc5d3f20ea4baa89e45f60f656b8a0f2caf0ff3