drm/i915: move drmP.h include to i915_drv.h

The intel_bios.h header doesn't even need it, but other headers included
from i915_drv.h do. Let's untangle the mess a bit.
Reviewed-by: NChris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: NJani Nikula <jani.nikula@intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/1450271061-32646-1-git-send-email-jani.nikula@intel.com

drivers/gpu/drm/i915/i915_drv.h

@@ -33,6 +33,7 @@
 #include <uapi/drm/i915_drm.h>
 #include <uapi/drm/drm_fourcc.h>
 
+#include <drm/drmP.h>
 #include "i915_reg.h"
 #include "intel_bios.h"
 #include "intel_ringbuffer.h"

drivers/gpu/drm/i915/intel_bios.h

@@ -28,8 +28,6 @@
 #ifndef _I830_BIOS_H_
 #define _I830_BIOS_H_
 
-#include <drm/drmP.h>
-
 struct vbt_header {
 	u8 signature[20];		/**< Always starts with 'VBT$' */
 	u16 version;			/**< decimal */