drm: move xe_pciids.h under include/drm/intel

Clean up the top level include/drm directory by grouping all the Intel
specific files under a common subdirectory.

Cc: Daniel Vetter <daniel@ffwll.ch>
Cc: Dave Airlie <airlied@gmail.com>
Cc: Lucas De Marchi <lucas.demarchi@intel.com>
Acked-by: Lucas De Marchi <lucas.demarchi@intel.com>
Acked-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/e19543f2ae978678c2ff814454f07c96ccd02175.1717075103.git.jani.nikula@intel.com

drivers/gpu/drm/xe/xe_pci.c

@@ -13,7 +13,7 @@
 
 #include <drm/drm_color_mgmt.h>
 #include <drm/drm_drv.h>
-#include <drm/xe_pciids.h>
+#include <drm/intel/xe_pciids.h>
 
 #include "display/xe_display.h"
 #include "regs/xe_gt_regs.h"