HAL_ChibiOS: adjust for changed flash API

libraries/AP_HAL_ChibiOS/Storage.cpp

@@ -250,7 +250,7 @@ bool Storage::_flash_write_data(uint8_t sector, uint32_t offset, const uint8_t *
 {
 #ifdef STORAGE_FLASH_PAGE
     size_t base_address = stm32_flash_getpageaddr(_flash_page+sector);
-    bool ret = stm32_flash_write(base_address+offset, data, length) == length;
+    bool ret = stm32_flash_write(base_address+offset, data, length);
     if (!ret && _flash_erase_ok()) {
         // we are getting flash write errors while disarmed. Try
         // re-writing all of flash

libraries/AP_HAL_ChibiOS/Util.cpp

@@ -262,9 +262,9 @@ bool Util::flash_bootloader()
     const uint8_t max_attempts = 10;
     for (uint8_t i=0; i<max_attempts; i++) {
         void *context = hal.scheduler->disable_interrupts_save();
-        const int32_t written = stm32_flash_write(addr, fw, fw_size);
+        bool ok = stm32_flash_write(addr, fw, fw_size);
         hal.scheduler->restore_interrupts(context);
-        if (written == -1 || written < fw_size) {
+        if (!ok) {
             hal.console->printf("Flash failed! (attempt=%u/%u)\n",
                                 i+1,
                                 max_attempts);