drm/i915: gen2: move error capture of IER to its correct place

While checking the error capture path I noticed that this register is
read twice for GEN2, so fix this and also move the read where it's done
for other platforms.

Signed-off-by: Imre Deak <imre.deak@intel.com>
Reviewed-by: Rodrigo Vivi <rodrigo.vivi@gmail.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
diff --git a/drivers/gpu/drm/i915/i915_gpu_error.c b/drivers/gpu/drm/i915/i915_gpu_error.c
index 282164c..667bb29 100644
--- a/drivers/gpu/drm/i915/i915_gpu_error.c
+++ b/drivers/gpu/drm/i915/i915_gpu_error.c
@@ -1054,9 +1054,6 @@
 		error->gfx_mode = I915_READ(GFX_MODE);
 	}
 
-	if (IS_GEN2(dev))
-		error->ier = I915_READ16(IER);
-
 	/* 2: Registers which belong to multiple generations */
 	if (INTEL_INFO(dev)->gen >= 7)
 		error->forcewake = I915_READ(FORCEWAKE_MT);
@@ -1080,7 +1077,10 @@
 	if (HAS_PCH_SPLIT(dev))
 		error->ier = I915_READ(DEIER) | I915_READ(GTIER);
 	else {
-		error->ier = I915_READ(IER);
+		if (IS_GEN2(dev))
+			error->ier = I915_READ16(IER);
+		else
+			error->ier = I915_READ(IER);
 		for_each_pipe(pipe)
 			error->pipestat[pipe] = I915_READ(PIPESTAT(pipe));
 	}