soc: fsl/qe: Use of_get_child_by_name helper

Use the of_get_child_by_name() helper instead of open coding searching
for the 'firmware' child node. This removes directly accessing the name
pointer as well.

Cc: Qiang Zhao <[e-mail]>
Cc: Li Yang <[e-mail]>
Cc: [e-mail]
Cc: [e-mail]
Signed-off-by: Rob Herring <[e-mail]>
Acked-by: Qiang Zhao <[e-mail]>
Signed-off-by: Li Yang <[e-mail]>

drivers/soc/fsl/qe/qe.c

···
 	}
 
 	/* Find the 'firmware' child node */
-	for_each_child_of_node(qe, fw) {
-		if (strcmp(fw->name, "firmware") == 0)
-			break;
-	}
-
+	fw = of_get_child_by_name(qe, "firmware");
 	of_node_put(qe);
 
 	/* Did we find the 'firmware' node? */