Basic read/write/erase flash functionality works from the CLI

Very little code coverage tested yet, only writes of small sizes

src/main/drivers/flash.h

@@ -0,0 +1,31 @@
+/*
+ * This file is part of Cleanflight.
+ *
+ * Cleanflight is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * Cleanflight is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with Cleanflight.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#pragma once
+
+#include <stdint.h>
+
+typedef struct flashGeometry_t {
+    uint8_t sectors;
+
+    uint16_t pagesPerSector;
+    uint16_t pageSize;
+
+    uint32_t sectorSize;
+
+    uint32_t totalSize;
+} flashGeometry_t;