next-cube: don't use rtc phase value of -1

The rtc phase value of -1 is directly equivalent to using a phase value of 0 so
simplify the logic to use an initial rtc phase of 0.

Signed-off-by: Mark Cave-Ayland <mark.cave-ayland@ilande.co.uk>
Reviewed-by: Thomas Huth <huth@tuxfamily.org>
Message-ID: <20241222130012.1013374-25-mark.cave-ayland@ilande.co.uk>
Signed-off-by: Thomas Huth <huth@tuxfamily.org>

hw/m68k/next-cube.c

@@ -265,9 +265,6 @@ static void next_scr2_rtc_update(NeXTPC *s)
 
     if (scr2_2 & 0x1) {
         /* DPRINTF("RTC %x phase %i\n", scr2_2, rtc->phase); */
-        if (rtc->phase == -1) {
-            rtc->phase = 0;
-        }
         /* If we are in going down clock... do something */
         if (((old_scr2 & SCR2_RTCLK) != (scr2_2 & SCR2_RTCLK)) &&
                 ((scr2_2 & SCR2_RTCLK) == 0)) {
@@ -282,7 +279,7 @@ static void next_scr2_rtc_update(NeXTPC *s)
         }
     } else {
         /* else end or abort */
-        rtc->phase = -1;
+        rtc->phase = 0;
         rtc->command = 0;
         rtc->value = 0;
     }