hal: renesas: rx: Fix the build warning in WDT source

The iwdt_rx called R_BSP_HardwareLock but does't include the header,
add header include to fix the build warning

Signed-off-by: Quy Tran <[email protected]>

Author: quytranpzz

drivers/rx/README

@@ -67,3 +67,7 @@ Patch List:
    because Zephyr SDK hasn't support it yet
    Impacted files:
       drivers/rx/rdp/src/r_bsp/mcu/all/r_rx_intrinsic_functions.h
+
+   * Fix the build warnings in IWDT driver
+   Impacted files:
+      drivers/rx/rdp/src/r_iwdt_rx/src/r_iwdt_rx.c

drivers/rx/rdp/src/r_iwdt_rx/src/r_iwdt_rx.c

@@ -37,6 +37,7 @@ Includes   <System Includes> , "Project Includes"
 /* Defines for IWDT support */
 #include "r_iwdt_rx_config.h"
 #include "r_iwdt_rx_if.h"
+#include "r_bsp_locking.h"
 
 /***********************************************************************************************************************
 Macro definitions