jiminy-mega256rfr2: add `BOOTLOADER_CLEARS_WATCHDOG_AND_PASSES_MCUSR`

This variable helps to inform at boot time that some
information about the booting process, e.g. reset cause.

boards/jiminy-mega256rfr2/include/board.h

@@ -101,6 +101,17 @@ extern "C" {
 #define BOOTLOADER_CLEARS_WATCHDOG_AND_PASSES_MCUSR 1
 /** @} */
 
+/**
+ * @name Indicate Watchdog cleared in bootloader an
+ *
+ * AVR CPUs need to reset the Watchdog as fast as possible.
+ * This flag indicates that the watchdog is reseted in the bootloader
+ * and that the MCUSR value is stored in register 2 (r2)
+ * @{
+ */
+#define BOOTLOADER_CLEARS_WATCHDOG_AND_PASSES_MCUSR 1
+/** @} */
+
 /**
  * @name CPU clock scale for jiminy-megarfr256rfr2
  *