Address the following denials:
<12>[  417.732129] type=1400 audit(365340.189:47): avc: denied { read } for pid=1737 comm="Binder_2" name="mmcblk0p18" dev="tmpfs" ino=12406 scontext=u:r:system_server:s0 tcontext=u:object_r:block_device:s0 tclass=blk_file permissive=0
<12>[  417.882126] type=1400 audit(365340.339:48): avc: denied { read } for pid=1737 comm="Binder_2" name="mmcblk0p18" dev="tmpfs" ino=12406 scontext=u:r:system_server:s0 tcontext=u:object_r:block_device:s0 tclass=blk_file permissive=0

(cherrypick of commit 47bd7300)

Bug: 16710840
Change-Id: I8cb5b4b17dffe14f0bf05d63eb8f6ab8d5c09f53