In targets.json, add the "IPV4" setting for RZ_A1H

We added "IPV4" of Compile Macro in "targets.json" file.
We failed in the reletion test of IPV4 because "IPV4" was not entered into our Build Target setting.

Author: TomoYamanaka

hal/targets.json

@@ -1510,7 +1510,8 @@
                 "template": ["iar_rz_a1h.ewp.tmpl"]
             }
         },
-        "device_has": ["ANALOGIN", "CAN", "ERROR_PATTERN", "ETHERNET", "I2C", "I2CSLAVE", "I2C_ASYNCH", "INTERRUPTIN", "PORTIN", "PORTINOUT", "PORTOUT", "PWMOUT", "RTC", "SERIAL", "SERIAL_ASYNCH", "SERIAL_FC", "SPI", "SPISLAVE", "SPI_ASYNCH", "STDIO_MESSAGES"]
+        "device_has": ["ANALOGIN", "CAN", "ERROR_PATTERN", "ETHERNET", "I2C", "I2CSLAVE", "I2C_ASYNCH", "INTERRUPTIN", "PORTIN", "PORTINOUT", "PORTOUT", "PWMOUT", "RTC", "SERIAL", "SERIAL_ASYNCH", "SERIAL_FC", "SPI", "SPISLAVE", "SPI_ASYNCH", "STDIO_MESSAGES"],
+        "features": ["IPV4"]
     },
     "VK_RZ_A1H": {
         "inherits": ["Target"],