drm/amd/display: remove no need NULL check before kfree

This change is to cleanup the code a bit.
Acked-by: Christian König <christian.koenig@amd.com>
Signed-off-by: Bernard Zhao <bernard@vivo.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

drivers/gpu/drm/amd/display/dc/dcn10/dcn10_resource.c

@@ -978,10 +978,8 @@ static void dcn10_resource_destruct(struct dcn10_resource_pool *pool)
 		pool->base.mpc = NULL;
 	}
 
-	if (pool->base.hubbub != NULL) {
-		kfree(pool->base.hubbub);
-		pool->base.hubbub = NULL;
-	}
+	kfree(pool->base.hubbub);
+	pool->base.hubbub = NULL;
 
 	for (i = 0; i < pool->base.pipe_count; i++) {
 		if (pool->base.opps[i] != NULL)
@@ -1011,14 +1009,10 @@ static void dcn10_resource_destruct(struct dcn10_resource_pool *pool)
 	for (i = 0; i < pool->base.res_cap->num_ddc; i++) {
 		if (pool->base.engines[i] != NULL)
 			dce110_engine_destroy(&pool->base.engines[i]);
-		if (pool->base.hw_i2cs[i] != NULL) {
-			kfree(pool->base.hw_i2cs[i]);
-			pool->base.hw_i2cs[i] = NULL;
-		}
-		if (pool->base.sw_i2cs[i] != NULL) {
-			kfree(pool->base.sw_i2cs[i]);
-			pool->base.sw_i2cs[i] = NULL;
-		}
+		kfree(pool->base.hw_i2cs[i]);
+		pool->base.hw_i2cs[i] = NULL;
+		kfree(pool->base.sw_i2cs[i]);
+		pool->base.sw_i2cs[i] = NULL;
 	}
 
 	for (i = 0; i < pool->base.audio_count; i++) {