Label /firmware as firmware_file.

This corrects an incorrect labeling of this filesystem (was
previously sdcard_external) and fixes a ueventd denial.

Addresses the following denials:

<5>[    4.739128] type=1400 audit(804445.290:5): avc:  denied  { read } for  pid=205 comm="ueventd" name="mba.mdt" dev="mmcblk0p1" ino=3 scontext=u:r:ueventd:s0 tcontext=u:object_r:sdcard_external:s0 tclass=file
<5>[    4.739285] type=1400 audit(804445.290:6): avc:  denied  { open } for  pid=205 comm="ueventd" name="mba.mdt" dev="mmcblk0p1" ino=3 scontext=u:r:ueventd:s0 tcontext=u:object_r:sdcard_external:s0 tclass=file
<5>[    4.739474] type=1400 audit(804445.290:7): avc:  denied  { getattr } for  pid=205 comm="ueventd" path="/firmware/image/mba.mdt" dev="mmcblk0p1" ino=3 scontext=u:r:ueventd:s0 tcontext=u:object_r:sdcard_external:s0 tclass=file

(cherrypicked from 674a5c2a3ad778eff30238a64e93bcb6f02168b7)

Change-Id: I2927eaad3259424bf09c8ed7c0878a6643bc3214
4 files changed