drm/msm: move irq utils to mdp_kms

We'll want basically the same thing for mdp5, so refactor it out so it
can be shared.

Signed-off-by: Rob Clark <robdclark@gmail.com>
diff --git a/drivers/gpu/drm/msm/msm_kms.h b/drivers/gpu/drm/msm/msm_kms.h
index f01e239..dc0d30f 100644
--- a/drivers/gpu/drm/msm/msm_kms.h
+++ b/drivers/gpu/drm/msm/msm_kms.h
@@ -49,8 +49,19 @@
 
 struct msm_kms {
 	const struct msm_kms_funcs *funcs;
+
+	/* irq handling: */
+	bool in_irq;
+	struct list_head irq_list;    /* list of mdp4_irq */
+	uint32_t vblank_mask;         /* irq bits set for userspace vblank */
 };
 
+static inline void msm_kms_init(struct msm_kms *kms,
+		const struct msm_kms_funcs *funcs)
+{
+	kms->funcs = funcs;
+}
+
 struct msm_kms *mdp4_kms_init(struct drm_device *dev);
 
 #endif /* __MSM_KMS_H__ */