skip _PRT entry for non-existent IOSAPICs

Hi,

On some machines that support I/O hot-plugging,
it happens that after boottime one or more IO SAPICs appear after hot-plug event. Even in that case, ACPI _PRT entries can exist for devices behind those IO SAPICs at boottime for future use.

Currently iosapic.c will give up parsing _PRT entries once one of them hits such a non-existent IO SAPIC.

This patch fixes the problem on 2.5 ia64 bk tree. For 2.4, we don't have this problem now.

Thanks,
---
Takayoshi Kochi <[email protected]>

@@ -752,7 +752,7 @@
 
 			if (index < 0) {
 				printk(KERN_WARNING"IOSAPIC: GSI 0x%x has no IOSAPIC!\n", gsi);
-				return;
+				continue;
 			}
 			addr = iosapic_lists[index].addr;
 			gsi_base = iosapic_lists[index].gsi_base;