Summary: - I noticed that ostest sometimes stops with DEBUGASSERT - Finally I found a bug that cpu1 can not disable interrupt - This commit initializes nvic to fix this bug Impact: - Only affects cxd56 in SMP mode Testing: - spresense:smp and spresense:wifi_smp with DEBUG_ASSERTIONS=y Signed-off-by: Masayuki Ishikawa <Masayuki.Ishikawa@jp.sony.com>