apply benchmarking hack to multiboot as well

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
diff --git a/fw_cfg.c b/fw_cfg.c
index 684c0f6..f8aea5a 100644
--- a/fw_cfg.c
+++ b/fw_cfg.c
@@ -99,6 +99,13 @@
 		mb->mmap_length += sizeof(*mbmem);
 	}
 
+#ifdef BENCHMARK_HACK
+	/* Exit just before getting to vmlinuz, so that it is easy
+	 * to time/profile the firmware.
+	 */
+	outb(0xf4, 1);
+#endif
+
 	fw_cfg_select(FW_CFG_KERNEL_ENTRY);
 	kernel_entry = (void *) fw_cfg_readl_le();
 	asm volatile("jmp *%2" : : "a" (0x2badb002), "b"(mb), "c"(kernel_entry));