hvmloader: Fix parsing Etherboot roms to avoid an infinite loop.

Signed-off-by: Yosuke Iwamatsu <y-iwamatsu@ab.jp.nec.com>

diff -r 324f772239a7 tools/firmware/hvmloader/hvmloader.c
--- a/tools/firmware/hvmloader/hvmloader.c	Tue Apr 08 09:46:57 2008 +0100
+++ b/tools/firmware/hvmloader/hvmloader.c	Wed Apr 09 15:31:21 2008 +0900
@@ -378,7 +378,10 @@ static int scan_etherboot_nic(void *copy
                  strncmp(pcih->signature, "PCIR", 4) ||
                  (pcih->vendor_id != vendor_id) ||
                  (pcih->device_id != device_id) )
+            {
+                rom = (char *)rom + rom->rom_size * 512;
                 continue;
+            }
 
             /* Find the PnP expansion header (if any). */
             pnph = ((rom->expansion_header_offset != 0)