drm/i915: save/restore interrupt state

On resume, if the interrupt state isn't restored correctly, we may end
up with a flood of unexpected or ill-timed interrupts, which could cause
the kernel to disable the interrupt or vblank events to happen at the
wrong time.  So save/restore them properly.

Signed-off-by: Dave Airlie <airlied@linux.ie>
diff --git a/drivers/char/drm/i915_drv.h b/drivers/char/drm/i915_drv.h
index 786460d..360f660 100644
--- a/drivers/char/drm/i915_drv.h
+++ b/drivers/char/drm/i915_drv.h
@@ -134,6 +134,7 @@
 	u32 saveVBLANK_A;
 	u32 saveVSYNC_A;
 	u32 saveBCLRPAT_A;
+	u32 savePIPEASTAT;
 	u32 saveDSPASTRIDE;
 	u32 saveDSPASIZE;
 	u32 saveDSPAPOS;
@@ -154,6 +155,7 @@
 	u32 saveVBLANK_B;
 	u32 saveVSYNC_B;
 	u32 saveBCLRPAT_B;
+	u32 savePIPEBSTAT;
 	u32 saveDSPBSTRIDE;
 	u32 saveDSPBSIZE;
 	u32 saveDSPBPOS;
@@ -182,6 +184,9 @@
 	u32 saveFBC_LL_BASE;
 	u32 saveFBC_CONTROL;
 	u32 saveFBC_CONTROL2;
+	u32 saveIER;
+	u32 saveIIR;
+	u32 saveIMR;
 	u32 saveSWF0[16];
 	u32 saveSWF1[16];
 	u32 saveSWF2[3];