device/cpu_device.c: Zero initialize struct

Don't rely on this being 0.

Change-Id: I7c0d16b6a265bf9c7abcfdf2f18a43706ee03ea1
Signed-off-by: Arthur Heymans <arthur@aheymans.xyz>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/69752
Reviewed-by: Kyösti Mälkki <kyosti.malkki@gmail.com>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Elyes Haouas <ehaouas@noos.fr>

src/device/cpu_device.c

@@ -7,7 +7,7 @@
 struct device *add_cpu_device(struct bus *cpu_bus, unsigned int apic_id,
 			      int enabled)
 {
-	struct device_path cpu_path;
+	struct device_path cpu_path = {};
 	struct device *cpu;
 
 	/* Build the CPU device path */