drm/msm/sde: fix debugfs creation order issues

Fix debugfs ordering issue that prevents debugfs registration
for DRM objects and sde_core_irq. DRM objects should not be
put into the debug sub-folder, but in the actual dri node
directory. This resolves an issue where the subdirectory is
not yet available when the DRM late registration callbacks
are invoked. Also fixes a similar issue where the core_irq
module attempts to register earlier than the debugfs dir
creation.

Change-Id: Ie0c5d15cf68e410ba663a5635a53451fac728f90
Signed-off-by: Lloyd Atkinson <latkinso@codeaurora.org>