hw/arm_sysctl.c: Add missing 'break' statements

Add some break statements that were accidentally omitted
from some cases of arm_sysctl_write(). The omission was
harmless because in both cases the following case did
an immediate break, but adding the breaks explicitly
placates static analysers and avoids weird behaviour if
the following register is ever implemented as something
other than a no-op.

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Blue Swirl <blauwirbel@gmail.com>

hw/arm_sysctl.c

@@ -199,6 +199,7 @@ static void arm_sysctl_write(void *opaque, hwaddr offset,
     switch (offset) {
     case 0x08: /* LED */
         s->leds = val;
+        break;
     case 0x0c: /* OSC0 */
     case 0x10: /* OSC1 */
     case 0x14: /* OSC2 */
@@ -295,6 +296,7 @@ static void arm_sysctl_write(void *opaque, hwaddr offset,
             /* On VExpress this register is unimplemented and will RAZ/WI */
             break;
         }
+        break;
     case 0x54: /* CLCDSER */
     case 0x64: /* DMAPSR0 */
     case 0x68: /* DMAPSR1 */