[IA64] MCA recovery: pfn_valid() needs a pfn

paddr needs to be shifted by PAGE_SHIFT to be valid
input for pfn_valid().
Signed-off-by: NRuss Anderson <rja@sgi.com>
Signed-off-by: NTony Luck <tony.luck@intel.com>

arch/ia64/kernel/mca_drv.c

@@ -88,7 +88,7 @@ mca_page_isolate(unsigned long paddr)
 	if (!ia64_phys_addr_valid(paddr))
 		return ISOLATE_NONE;
 
-	if (!pfn_valid(paddr))
+	if (!pfn_valid(paddr >> PAGE_SHIFT))
 		return ISOLATE_NONE;
 
 	/* convert physical address to physical page number */