AMD graphics regression since Tails 2.10

This was reported against Tails 2.10 on #11850 (closed). According to https://bugs.debian.org/838858 and its duplicates, this should be fixed in firmware-amd-graphics 20161130-1. IMO we should upgrade to the latest version of that package in Tails 2.11.

Related issues

Related to #11850 (closed)
Blocked by #12122 (closed)
Blocked by #12298 (closed)

Original created by @intrigeri on 12218 (Redmine)

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