drm/vblank: Switch to bool in_vblank_irq in get_vblank_timestamp

It's overkill to have a flag parameter which is essentially used just
as a boolean. This takes care of core + adjusting drivers.

Adjusting the scanout position callback is a bit harder, since radeon
also supplies it's own driver-private flags in there.

v2: Fixup misplaced hunks (Neil).

v3: kbuild says v1 was better ...

Cc: Mario Kleiner <mario.kleiner@tuebingen.mpg.de>
Cc: Eric Anholt <eric@anholt.net>
Cc: Rob Clark <robdclark@gmail.com>
Cc: linux-arm-msm@vger.kernel.org
Cc: freedreno@lists.freedesktop.org
Cc: Alex Deucher <alexander.deucher@amd.com>
Cc: Christian König <christian.koenig@amd.com>
Cc: Ben Skeggs <bskeggs@redhat.com>
Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Reviewed-by: Neil Armstrong <narmstrong@baylibre.com>
Signed-off-by: Daniel Vetter <daniel.vetter@intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/20170509140329.24114-2-daniel.vetter@ffwll.ch

include/drm/drm_drv.h

@@ -241,8 +241,10 @@ struct drm_driver {
 	 *     DRM device.
 	 * pipe:
 	 *     Id of the crtc to query.
-	 * flags:
-	 *     Flags from the caller (DRM_CALLED_FROM_VBLIRQ or 0).
+	 * in_vblank_irq:
+	 *     True when called from drm_crtc_handle_vblank().  Some drivers
+	 *     need to apply some workarounds for gpu-specific vblank irq quirks
+	 *     if flag is set.
 	 * vpos:
 	 *     Target location for current vertical scanout position.
 	 * hpos:
@@ -308,11 +310,10 @@ struct drm_driver {
 	 *     Returns true upper bound on error for timestamp.
 	 * vblank_time:
 	 *     Target location for returned vblank timestamp.
-	 * flags:
-	 *     0 = Defaults, no special treatment needed.
-	 *     DRM_CALLED_FROM_VBLIRQ = Function is called from vblank
-	 *     irq handler. Some drivers need to apply some workarounds
-	 *     for gpu-specific vblank irq quirks if flag is set.
+	 * in_vblank_irq:
+	 *     True when called from drm_crtc_handle_vblank().  Some drivers
+	 *     need to apply some workarounds for gpu-specific vblank irq quirks
+	 *     if flag is set.
 	 *
 	 * Returns:
 	 *
@@ -322,7 +323,7 @@ struct drm_driver {
 	bool (*get_vblank_timestamp) (struct drm_device *dev, unsigned int pipe,
 				     int *max_error,
 				     struct timeval *vblank_time,
-				     unsigned flags);
+				     bool in_vblank_irq);
 
 	/* these have to be filled in */