Use libdrm-imx headers

Change-Id: Ie099536810d9142744ee40002543197edad93d22
diff --git a/libweston/compositor-drm.c b/libweston/compositor-drm.c
index 3365d29..16feccc 100644
--- a/libweston/compositor-drm.c
+++ b/libweston/compositor-drm.c
@@ -45,6 +45,8 @@
 #include <xf86drm.h>
 #include <xf86drmMode.h>
 #include <drm_fourcc.h>
+#include <drm_fourcc_imx.h>
+#include <libdrm/drm_mode_imx.h>
 
 #include <gbm.h>
 #include <libudev.h>
diff --git a/libweston/pixel-formats.c b/libweston/pixel-formats.c
index 1ea1b19..c2d4106 100644
--- a/libweston/pixel-formats.c
+++ b/libweston/pixel-formats.c
@@ -30,6 +30,7 @@
 #include <stdbool.h>
 #include <unistd.h>
 #include <drm_fourcc.h>
+#include <drm_fourcc_imx.h>
 
 #include "helpers.h"
 #include "wayland-util.h"