m7-common: fstab: Add misc partition

The misc partition is used for certain recovery actions. The bootloader
message is at offset location 2048 (0x800).

Change-Id: I8c4a036026b33b9a1b895d83fd3356a83e9ae4e8
Merge branch 'cm-11.0' of github.com:kbc-developers/android_device_htc_m7-common into cm-11.0