drm/i915: don't clobber the pipe param in sanitize_modesetting

... we need it later on in the function to clean up pipe <-> plane
associations. This regression has been introduced in

commit f47166d2
Author: Chris Wilson <chris@chris-wilson.co.uk>
Date:   Thu Mar 22 15:00:50 2012 +0000

    drm/i915: Sanitize BIOS debugging bits from PIPECONF

Spotted by staring at debug output of an (as it turns out) totally
unrelated bug.

v2: I've totally failed to do the s/pipe/i/ correctly, spotted by
Chris Wilson.
Reviewed-by: NChris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: NEugeni Dodonov <eugeni.dodonov@intel.com>
Cc: stable@kernel.org (the regression was Cc: stable, too)
Signed-Off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

drivers/gpu/drm/i915/intel_display.c

@@ -6253,10 +6253,11 @@ static void intel_sanitize_modesetting(struct drm_device *dev,
 {
 	struct drm_i915_private *dev_priv = dev->dev_private;
 	u32 reg, val;
+	int i;
 
 	/* Clear any frame start delays used for debugging left by the BIOS */
-	for_each_pipe(pipe) {
-		reg = PIPECONF(pipe);
+	for_each_pipe(i) {
+		reg = PIPECONF(i);
 		I915_WRITE(reg, I915_READ(reg) & ~PIPECONF_FRAME_START_DELAY_MASK);
 	}