hw/timer/grlib_gptimer: Avoid integer overflows

The GPTIMER uses 32-bit registers.  Use a 64-bit operation to get the
ptimer count, otherwise we end up with a count of 0 for GPTIMER counter
values of 0xffffffff.

Use the GPTIMER counter value for tracing to avoid an overflow of the
32-bit value passed to trace_grlib_gptimer_enable().
Reviewed-by: NFabien Chouteau <chouteau@adacore.com>
Signed-off-by: NSebastian Huber <sebastian.huber@embedded-brains.de>
Signed-off-by: NMichael Tokarev <mjt@tls.msk.ru>

hw/timer/grlib_gptimer.c

@@ -106,9 +106,9 @@ static void grlib_gptimer_enable(GPTimer *timer)
     /* ptimer is triggered when the counter reach 0 but GPTimer is triggered at
        underflow. Set count + 1 to simulate the GPTimer behavior. */
 
-    trace_grlib_gptimer_enable(timer->id, timer->counter + 1);
+    trace_grlib_gptimer_enable(timer->id, timer->counter);
 
-    ptimer_set_count(timer->ptimer, timer->counter + 1);
+    ptimer_set_count(timer->ptimer, (uint64_t)timer->counter + 1);
     ptimer_run(timer->ptimer, 1);
 }