x86: add missing break in hwdom_pit_access()

Coverity ID 1203045

Signed-off-by: Jan Beulich <jbeulich@xxxxxxxx>

--- a/xen/arch/x86/time.c
+++ b/xen/arch/x86/time.c
@@ -1634,6 +1634,7 @@ int hwdom_pit_access(struct ioreq *ioreq
             outb(ioreq->data, PIT_MODE);
             return 1;
         }
+        break;
 
     case 0x61:
         if ( ioreq->dir == IOREQ_READ )