stm32: add minimal stm32wlex5 / lorae5 target

credit to ofauchon

targets/lorae5.json

@@ -0,0 +1,12 @@
+{
+	"inherits": [
+		"stm32wle5"
+	],
+	"build-tags": [
+		"lorae5"
+	],
+	"serial": "uart",
+	"flash-method": "openocd",
+	"openocd-interface": "stlink-v2",
+	"openocd-target": "stm32wlx"
+}

targets/stm32wle5.json

@@ -0,0 +1,8 @@
+{
+    "inherits": ["cortex-m4"],
+    "build-tags": ["stm32wle5", "stm32"],
+    "extra-files": [
+      "src/device/stm32/stm32wle5.s"
+    ],
+    "linkerscript": "targets/stm32wle5.ld"
+}

targets/stm32wle5.ld

@@ -0,0 +1,10 @@
+
+MEMORY
+{
+    FLASH_TEXT (rw) : ORIGIN = 0x08000000, LENGTH = 256K
+    RAM (xrw)       : ORIGIN = 0x20000000, LENGTH = 64K
+}
+
+_stack_size = 4K;
+
+INCLUDE "targets/arm.ld"