drm/i915: fix gen4 gpu reset

While trying to fix up gen4 gpu reset in

commit f49f0586
Author: Kenneth Graunke <kenneth@whitecape.org>
Date:   Sat Sep 11 01:19:14 2010 -0700

    drm/i915: Actually set the reset bit in i965_reset

a little confusion about when wait_for times out has been introduced -
wait for loops _until_ the condition is true.

This fixes gpu reset on my gm45, testing with my hangman code shows
that it's now fairly reliable - it only died after well over 100 reset
cycles.

Cc: Eric Anholt <eric@anholt.net>
Reviewed-by: Kenneth Graunke <kenneth@whitecape.org>
Reviewed-by: Eugeni Dodonov <eugeni.dodonov@intel.com>
Signed-Off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

drivers/gpu/drm/i915/i915_drv.c

@@ -707,7 +707,7 @@ static int i965_reset_complete(struct drm_device *dev)
 {
 	u8 gdrst;
 	pci_read_config_byte(dev->pdev, I965_GDRST, &gdrst);
-	return gdrst & 0x1;
+	return (gdrst & GRDOM_RESET_ENABLE) == 0;
 }
 
 static int i965_do_reset(struct drm_device *dev)