drm/display: Move HDCP helpers into display-helper module

Move DRM's HDCP helper library into the display/ subdirectory and add
it to DRM's display helpers. Split the header file into core and helpers.
Update all affected drivers. No functional changes.

v3:
	* fix Kconfig dependencies
v2:
	* fix include statements (Jani, Javier)
	* update Kconfig symbols

Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Reviewed-by: Javier Martinez Canillas <javierm@redhat.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20220421073108.19226-7-tzimmermann@suse.de
diff --git a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
index 7ef20da6..e3130b4 100644
--- a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
+++ b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
@@ -48,7 +48,7 @@
 #include "amdgpu_dm.h"
 #ifdef CONFIG_DRM_AMD_DC_HDCP
 #include "amdgpu_dm_hdcp.h"
-#include <drm/drm_hdcp.h>
+#include <drm/display/drm_hdcp_helper.h>
 #endif
 #include "amdgpu_pm.h"
 #include "amdgpu_atombios.h"