Add MCU description, fix pin validation errors

Author: multiplemonomials

targets/TARGET_GigaDevice/TARGET_GD32F4XX/TARGET_GD32F450ZI/PinNames.h

@@ -233,15 +233,12 @@ typedef enum {
     ARDUINO_UNO_D15 = PORTB_8,
 #endif
 
-    LED1        = PORTF_6,
-    LED2        = PORTC_13,
-    LED3        = PORTE_6,
+#define LED1 PORTF_6
+#define LED2 PORTC_13
+#define LED3 PORTE_6
 
-    KEY1        = PORTE_5,
-    KEY2        = PORTE_4,
-
-    BUTTON1     = KEY1,
-    BUTTON2     = KEY2,
+#define BUTTON1 PORTE_5
+#define BUTTON2 PORTE_4
 
     SERIAL_TX   = PORTC_12,
     SERIAL_RX   = PORTD_2,

targets/cmsis_mcu_descriptions.json5

@@ -1261,6 +1261,78 @@
         "sub_family": "EFR32MG12P332",
         "vendor": "Silicon Labs:21"
     },
+    "GD32F307VG": {
+        "algorithms": [
+            {
+                "default": true,
+                "file_name": "Flash/GD32F30x_CL.FLM",
+                "ram_size": null,
+                "ram_start": null,
+                "size": 1048576,
+                "start": 134217728,
+                "style": "Keil"
+            }
+        ],
+        "family": "GD32F30x Series",
+        "from_pack": {
+            "pack": "GD32F30x_DFP",
+            "url": "https://gd32mcu.com/data/documents/pack/",
+            "vendor": "GigaDevice",
+            "version": "2.2.1"
+        },
+        "memories": {
+            "IRAM1": {
+                "access": {
+                    "execute": false,
+                    "non_secure": false,
+                    "non_secure_callable": false,
+                    "peripheral": false,
+                    "read": true,
+                    "secure": false,
+                    "write": true
+                },
+                "default": true,
+                "p_name": null,
+                "size": 98304,
+                "start": 536870912,
+                "startup": false
+            },
+            "IROM1": {
+                "access": {
+                    "execute": true,
+                    "non_secure": false,
+                    "non_secure_callable": false,
+                    "peripheral": false,
+                    "read": true,
+                    "secure": false,
+                    "write": false
+                },
+                "default": true,
+                "p_name": null,
+                "size": 1048576,
+                "start": 134217728,
+                "startup": true
+            }
+        },
+        "name": "GD32F307VG",
+        "processors": [
+            {
+                "address": null,
+                "ap": 0,
+                "apid": null,
+                "core": "CortexM4",
+                "default_reset_sequence": null,
+                "dp": 0,
+                "fpu": "SinglePrecision",
+                "mpu": "Present",
+                "name": null,
+                "svd": "SVD/GD32F30x_CL.svd",
+                "unit": 0
+            }
+        ],
+        "sub_family": "GD32F307",
+        "vendor": "GigaDevice:123"
+    },
     "GD32F450ZI": {
         "algorithms": [
             {