x86: Fix a warning with gcc 4.4.4

This warning appears even though it seems that the compiler could work it
out. Fix it.

Signed-off-by: Simon Glass <sjg@chromium.org>
diff --git a/arch/x86/cpu/cpu.c b/arch/x86/cpu/cpu.c
index a4e639d..3583619 100644
--- a/arch/x86/cpu/cpu.c
+++ b/arch/x86/cpu/cpu.c
@@ -238,6 +238,7 @@
 	int i;
 
 	vendor_name[0] = '\0'; /* Unset */
+	cpu->device = 0; /* fix gcc 4.4.4 warning */
 
 	/* Find the id and vendor_name */
 	if (!has_cpuid()) {