enrc2b: Fix /dev/block/mmcblk0p2 permission

The HTC camera blobs read calibration data from this partition. The
mediaserver runs with uid media and gid audio.

Fixes the following errors when the mediaserver is starting:

E/STT:emmc(157): emmc_open(): /dev/block/mmcblk0p2: Permission denied
E/STT:partition(157): partition_open(): cannot find partition [WDM]!
E/        (157): [Flash Calibration] : partition_open ["WDM"] failed, errno = 13 (Permission denied)! Use original cfg value.

Change-Id: Ie3c1347a7eddc5fe4d5f00770895d0f450dc4537
Merge "enrc2b: Fix /dev/block/mmcblk0p2 permission" into cm-11.0