Fix so no files in drm/amd/ depends on the
deprecated drm_os_linux.h header file.

It was done manually:
- remove drm_os_linux.h from drmP.h
- fix all build errros
Signed-off-by: NSam Ravnborg <sam@ravnborg.org>
Reviewed-by: NAlex Deucher <alexander.deucher@amd.com>
Cc: "Christian König" <christian.koenig@amd.com>
Cc: "David (ChunMing) Zhou" <David1.Zhou@amd.com>
Cc: David Airlie <airlied@linux.ie>
Cc: Daniel Vetter <daniel@ffwll.ch>
Link: https://patchwork.freedesktop.org/patch/msgid/20190609220757.10862-3-sam@ravnborg.org