Description: arm64: Enforce BBM for huge IO/VMAP mappings
References:
 https://source.android.com/security/bulletin/pixel/2019-09-01
Notes:
 carnil> Commit fixes 324420bf91f6 ("arm64: add support for ioremap()
 carnil> block mappings") which is in 4.6-rc1.
Bugs:
upstream: released (4.16-rc3) [15122ee2c515a253b0c66a3e618bc7ebe35105eb]
4.19-upstream-stable: N/A "Fixed before branching point"
4.9-upstream-stable: needed
3.16-upstream-stable: N/A "Vulnerable code not present"
sid: released (4.16.5-1)
4.19-buster-security: N/A "Fixed before branching point"
4.9-stretch-security: needed
3.16-jessie-security: N/A "Vulnerable code not present"