x86: fix 64k corruption-check

Impact: fix boot crash

Need to exit early if the addr is far above 64k.

The crash got exposed by:

  78a8b35: x86: make e820_update_range() handle small range update
Signed-off-by: Yinghai Lu <yinghai@kernel.org>
Cc: <stable@kernel.org>
LKML-Reference: <49BC2279.2030101@kernel.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

arch/x86/kernel/check.c

@@ -86,12 +86,12 @@ void __init setup_bios_corruption_check(void)
 		if (!(addr + 1))
 			break;
 
+		if (addr >= corruption_check_size)
+			break;
+
 		if ((addr + size) > corruption_check_size)
 			size = corruption_check_size - addr;
 
-		if (size == 0)
-			break;
-
 		e820_update_range(addr, size, E820_RAM, E820_RESERVED);
 		scan_areas[num_scan_areas].addr = addr;
 		scan_areas[num_scan_areas].size = size;