drm/i915: IS_IRONLAKE is synonymous with gen == 5

So remove the redundant bit in the capabilities block and
s/IS_IRONLAKE/IS_GEN5/.

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
diff --git a/drivers/gpu/drm/i915/i915_gem_tiling.c b/drivers/gpu/drm/i915/i915_gem_tiling.c
index 8c9ffc4..af352de 100644
--- a/drivers/gpu/drm/i915/i915_gem_tiling.c
+++ b/drivers/gpu/drm/i915/i915_gem_tiling.c
@@ -92,7 +92,7 @@
 	uint32_t swizzle_x = I915_BIT_6_SWIZZLE_UNKNOWN;
 	uint32_t swizzle_y = I915_BIT_6_SWIZZLE_UNKNOWN;
 
-	if (IS_IRONLAKE(dev) || IS_GEN6(dev)) {
+	if (IS_GEN5(dev) || IS_GEN6(dev)) {
 		/* On Ironlake whatever DRAM config, GPU always do
 		 * same swizzling setup.
 		 */