disp: msm: avoid using #ifdef for configurations

Use #if IS_ENABLED() instead of #ifdef for configurations as vendor module
guidelines.

Use #if IS_ENABLED(CONFIG_XXX) instead of #ifdef CONFIG_XXX to ensure that
the code inside the #if block continues to compile if the config changes
to a tristate config in the future.

The differences are as follows:
	1.#if IS_ENABLED(CONFIG_XXX) evaluates to true when CONFIG_XXX is set to
		module (=m) or built-in (=y).
	2.#ifdef CONFIG_XXX evaluates to true when CONFIG_XXX is set to
		built-in(=y) , but doesn't when CONFIG_XXX is set to module(=m).
		Use this only when you're certain you want to do the same thing
		when the config is set to module or is disabled.

Change-Id: Ia806b9b01ad8414d0e4de027a382cb68e7fb4a6a
Signed-off-by: GG Hou <quic_renjhou@quicinc.com>

msm/dp/dp_aux_bridge.h

@@ -1,4 +1,5 @@
 /*
+ * Copyright (c) 2021-2022 Qualcomm Innovation Center, Inc. All rights reserved.
  * Copyright (c) 2019-2021, The Linux Foundation. All rights reserved.
  *
  * This program is free software; you can redistribute it and/or modify
@@ -59,9 +60,9 @@ enum dp_aux_bridge_flag {
  * @head: to keep track of all added bridges
  */
 struct dp_aux_bridge {
-#ifdef CONFIG_OF
+#if IS_ENABLED(CONFIG_OF)
 	struct device_node *of_node;
-#endif
+#endif /* CONFIG_OF */
 	void *dev_priv;
 	u32 flag;
 	void *mst_ctx;
@@ -116,14 +117,14 @@ struct dp_aux_bridge {
  */
 int dp_aux_add_bridge(struct dp_aux_bridge *bridge);
 
-#ifdef CONFIG_OF
+#if IS_ENABLED(CONFIG_OF)
 /**
  * of_dp_aux_find_bridge - Find registered DP aux bridge
  * @np: device node pointer to the bridge
  * return: DP aux bridge pointer, NULL if not found
  */
 struct dp_aux_bridge *of_dp_aux_find_bridge(struct device_node *np);
-#endif
+#endif /* CONFIG_OF */
 
 #endif /* _DP_AUX_BRIDGE_H_ */