style: Inconsistent macro names changed

Fix incorrect header file pre-macro names in
'dts/common'.

Signed-off-by: James Roy <rruuaanng@outlook.com>

dts/common/freq.h

@@ -4,10 +4,10 @@
  * SPDX-License-Identifier: Apache-2.0
  */
 
-#ifndef __DT_FREQ_H
-#define __DT_FREQ_H
+#ifndef ZEPHYR_DTS_COMMON_FREQ_H_
+#define ZEPHYR_DTS_COMMON_FREQ_H_
 
 #define DT_FREQ_K(x) ((x) * 1000)
 #define DT_FREQ_M(x) (DT_FREQ_K(x) * 1000)
 
-#endif /* __DT_FREQ_H */
+#endif /* ZEPHYR_DTS_COMMON_FREQ_H_ */

dts/common/mem.h

@@ -4,8 +4,8 @@
  * SPDX-License-Identifier: Apache-2.0
  */
 
-#ifndef __DT_MEM_H
-#define __DT_MEM_H
+#ifndef ZEPHYR_DTS_COMMON_MEM_H_
+#define ZEPHYR_DTS_COMMON_MEM_H_
 
 #define DT_SIZE_K(x) ((x) * 1024)
 #define DT_SIZE_M(x) (DT_SIZE_K(x) * 1024)
@@ -15,4 +15,4 @@
 
 #define DT_ADDR(a) _DT_DO_CONCAT(0x, a)
 
-#endif /* __DT_MEM_H */
+#endif /* ZEPHYR_DTS_COMMON_MEM_H_ */