[apps] :recycle: Clean-up sign conversion warnings from sleep_wakeup
#include "runtime.h"
#include "synchronization.h"
-volatile uint32_t atomic __attribute__((section(".l2"))) = -1;
+volatile uint32_t atomic __attribute__((section(".l2"))) = (uint32_t)-1;
extern volatile uint32_t tcdm_start_address_reg;
extern volatile uint32_t tcdm_end_address_reg;
