drm/radeon: update line buffer allocation for dce4.1/5

We need to allocate line buffer to each display when
setting up the watermarks.  Failure to do so can lead
to a blank screen.  This fixes blank screen problems
on dce4.1/5 asics.

from a proposed Linux patch by Alex Deucher of AMD.
drm/radeon: update line buffer allocation for dce6

We need to allocate line buffer to each display when
setting up the watermarks.  Failure to do so can lead
to a blank screen.  This fixes blank screen problems
on dce6 asics.

Fixes:
https://bugs.freedesktop.org/show_bug.cgi?id=64850

from a proposed Linux patch by Alex Deucher of AMD.

Fixes problems with multiple displays on pitcairn
reported by Alexis de BRUYN.
Properly pass daemon_flags to amd(8).

ok dcoppa@ sthen@