drm/radeon/kms: fix interlaced modes on dce4+

- set scaler table clears the interleave bit, need to
reset it in encoder quirks, this was already done for
pre-dce4.
- remove the interleave settings from set_base() functions
this is now handled in the encoder quirks functions, and
isn't technically part of the display base setup.
- rename evergreen_do_set_base() to dce4_do_set_base() since
it's used on both evergreen and NI asics.

Fixes:
https://bugzilla.kernel.org/show_bug.cgi?id=28182



Signed-off-by: Alex Deucher <alexdeucher@gmail.com>
Cc: stable@kernel.org
Signed-off-by: Dave Airlie <airlied@redhat.com>