arch/arm/src/lpc43xx: Make WWDT usable again LPC43xx WWDT driver was not updated when irq_dispatch grew an argument flag in b3222bbc8a18af33eef38a147165ee1999124b21. Also fixes two typos and a naming inconsistency (WWDT vs. WWDG). Approved-by: GregoryN <gnutt@nuttx.org>