drm/i915: Replace a few for_each_pipe(i) by for_each_pipe(pipe)

Consistency throughout the code base is good and remove some room for
mistakes (as explained in the "drm/i915: Use a pipe variable to cycle
through the pipes" commit)

So, let's replace the for_each_pipe(i) occurences by for_each_pipe(pipe)
when it's reasonable and practical to do so (eg. when there isn't another
pipe variable already).

Suggested-by: Chris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: Damien Lespiau <damien.lespiau@intel.com>
Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
diff --git a/drivers/gpu/drm/i915/intel_pm.c b/drivers/gpu/drm/i915/intel_pm.c
index 5819f5c..8df1826 100644
--- a/drivers/gpu/drm/i915/intel_pm.c
+++ b/drivers/gpu/drm/i915/intel_pm.c
@@ -4792,7 +4792,7 @@
 static void gen8_init_clock_gating(struct drm_device *dev)
 {
 	struct drm_i915_private *dev_priv = dev->dev_private;
-	enum pipe i;
+	enum pipe pipe;
 
 	I915_WRITE(WM3_LP_ILK, 0);
 	I915_WRITE(WM2_LP_ILK, 0);
@@ -4837,9 +4837,9 @@
 		   I915_READ(CHICKEN_PAR1_1) | DPA_MASK_VBLANK_SRD);
 
 	/* WaPsrDPRSUnmaskVBlankInSRD:bdw */
-	for_each_pipe(i) {
-		I915_WRITE(CHICKEN_PIPESL_1(i),
-			   I915_READ(CHICKEN_PIPESL_1(i) |
+	for_each_pipe(pipe) {
+		I915_WRITE(CHICKEN_PIPESL_1(pipe),
+			   I915_READ(CHICKEN_PIPESL_1(pipe) |
 				     DPRS_MASK_VBLANK_SRD));
 	}
 
@@ -5310,7 +5310,7 @@
 static void hsw_power_well_post_disable(struct drm_i915_private *dev_priv)
 {
 	struct drm_device *dev = dev_priv->dev;
-	enum pipe p;
+	enum pipe pipe;
 	unsigned long irqflags;
 
 	/*
@@ -5321,9 +5321,9 @@
 	 * FIXME: Should we do this in general in drm_vblank_post_modeset?
 	 */
 	spin_lock_irqsave(&dev->vbl_lock, irqflags);
-	for_each_pipe(p)
-		if (p != PIPE_A)
-			dev->vblank[p].last = 0;
+	for_each_pipe(pipe)
+		if (pipe != PIPE_A)
+			dev->vblank[pipe].last = 0;
 	spin_unlock_irqrestore(&dev->vbl_lock, irqflags);
 }