drm/mga: make header file self contained

This makes migration away from drmP.h simple
as we do not need to duplicate dependencies required by mga_drv.h

Signed-off-by: Sam Ravnborg <sam@ravnborg.org>
Acked-by: Thomas Zimmermann <tzimmermann@suse.de>
Cc: Daniel Vetter <daniel@ffwll.ch>
Cc: David Airlie <airlied@linux.ie>
Link: https://patchwork.freedesktop.org/patch/msgid/20190623103542.30697-3-sam@ravnborg.org

drivers/gpu/drm/mga/mga_drv.h

@@ -31,7 +31,20 @@
 #ifndef __MGA_DRV_H__
 #define __MGA_DRV_H__
 
+#include <linux/irqreturn.h>
+#include <linux/slab.h>
+
+#include <drm/drm_agpsupport.h>
+#include <drm/drm_device.h>
+#include <drm/drm_file.h>
+#include <drm/drm_ioctl.h>
+#include <drm/drm_irq.h>
 #include <drm/drm_legacy.h>
+#include <drm/drm_pci.h>
+#include <drm/drm_print.h>
+#include <drm/drm_sarea.h>
+#include <drm/drm_vblank.h>
+#include <drm/mga_drm.h>
 
 /* General customization:
  */