drm/msm/dpu: Refactor resource manager

Track hardware resource objects in arrays rather than
a list and remove the resource manager's iterator idiom. Separate
the mapping of hardware resources to an encoder ID into a different
array.

Use an implicit mapping between the hardware blocks' ids, which
are 1-based, and array indices in these arrays to replace iteration
with index lookups in several places.

Signed-off-by: Drew Davenport <ddavenport@chromium.org>
[squash in minor compiler warning fixes]
Signed-off-by: Rob Clark <robdclark@chromium.org>