lsi: Fix value overflow in request tag processing

This fixes a mismerge of 64d56409 (wrong
patch version): We need to mask the tag value properly to obtain its
device ID.
Signed-off-by: NJan Kiszka <jan.kiszka@siemens.com>
Signed-off-by: NAurelien Jarno <aurelien@aurel32.net>

hw/lsi53c895a.c

@@ -543,7 +543,7 @@ static void lsi_do_dma(LSIState *s, int out)
         return;
     }
 
-    id = s->current->tag >> 8;
+    id = (s->current->tag >> 8) & 0xf;
     dev = s->bus.devs[id];
     if (!dev) {
         lsi_bad_selection(s, id);
@@ -745,7 +745,7 @@ static void lsi_do_command(LSIState *s)
     s->sfbr = buf[0];
     s->command_complete = 0;
 
-    id = s->select_tag >> 8;
+    id = (s->select_tag >> 8) & 0xf;
     dev = s->bus.devs[id];
     if (!dev) {
         lsi_bad_selection(s, id);