Partly revert "drm/hyperv: Remove reference to hyperv_fb driver"

This partly reverts commit 8f582bcd132c ("drm/hyperv: Remove reference
to hyperv_fb driver") which was messed up by me while trying to fix a
merge conflict.

Signed-off-by: Helge Deller <deller@gmx.de>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>