Revert "drm/panel: Add and fill drm_panel type field"

This reverts commit 64b76abf which is
commit 9a2654c0 upstream.

It breaks the Android abi and is not needed for any Android systems.  If
it is required in the future, it can come back in an abi-safe way.

Bug: 161946584
Change-Id: Idfbd072361ba097010fc168a3a81aa853c0b6b0e
Signed-off-by: Greg Kroah-Hartman <gregkh@google.com>