Add "RZ_A1XX" label for commonizing in targets.json

I added the "RZ_A1XX" label for commonizing the setting in targets.json, and inherited in both RZ_A1H and VK_RZ_A1H.

Author: TomoYamanaka

targets/targets.json

@@ -2426,27 +2426,24 @@
         "features": ["BLE"],
         "release_versions": ["2", "5"]
     },
-    "RZ_A1H": {
-        "supported_form_factors": ["ARDUINO"],
+    "RZ_A1XX": {
+        "inherits": ["Target"],
         "core": "Cortex-A9",
-        "program_cycle_s": 2,
-        "extra_labels": ["RENESAS", "RZ_A1XX", "RZA1H", "MBRZA1H"],
         "supported_toolchains": ["ARM", "GCC_ARM", "IAR"],
-        "inherits": ["Target"],
+        "extra_labels": ["RENESAS", "RZ_A1XX"],
         "device_has": ["ANALOGIN", "CAN", "ETHERNET", "I2C", "I2CSLAVE", "I2C_ASYNCH", "INTERRUPTIN", "PORTIN", "PORTINOUT", "PORTOUT", "PWMOUT", "RTC", "SERIAL", "SERIAL_ASYNCH", "SERIAL_FC", "SPI", "SPISLAVE", "SPI_ASYNCH", "STDIO_MESSAGES"],
         "features": ["LWIP"],
+        "program_cycle_s": 2
+    },
+    "RZ_A1H": {
+        "inherits": ["RZ_A1XX"],
+        "supported_form_factors": ["ARDUINO"],
+        "extra_labels_add": ["RZA1H", "MBRZA1H"],
         "release_versions": ["2", "5"]
     },
     "VK_RZ_A1H": {
-        "inherits": ["Target"],
-        "core": "Cortex-A9",
-        "extra_labels": ["RENESAS", "RZ_A1XX", "RZA1H", "VKRZA1H"],
-        "supported_toolchains": ["ARM", "GCC_ARM", "IAR"],
-        "default_toolchain": "ARM",
-        "program_cycle_s": 2,
-        "device_has": ["ANALOGIN", "CAN", "ETHERNET", "I2C", "I2CSLAVE", "INTERRUPTIN", "PORTIN", "PORTINOUT", "PORTOUT", "PWMOUT", "RTC", "SERIAL", "SERIAL_FC", "SPI", "SPISLAVE", "STDIO_MESSAGES"],
-        "features": ["LWIP"],
-        "default_lib": "std",
+        "inherits": ["RZ_A1XX"],
+        "extra_labels": ["RZA1H", "VKRZA1H"],
         "release_versions": []
     },
     "MAXWSNENV": {