CPU: Declare cpu_phys_address_size() for all arch

Resource allocator and 64-bit PCI BARs will need it and
PCI use is not really restricted to x86.

Change-Id: Ie97f0f73380118f43ec6271aed5617d62a4f5532
Signed-off-by: Kyösti Mälkki <kyosti.malkki@gmail.com>
Reviewed-on: https://review.coreboot.org/17733
Tested-by: build bot (Jenkins)
Reviewed-by: Aaron Durbin <adurbin@chromium.org>

src/include/cpu/cpu.h

@@ -8,6 +8,7 @@ void cpu_initialize(unsigned int cpu_index);
 struct bus;
 void initialize_cpus(struct bus *cpu_bus);
 void asmlinkage secondary_cpu_init(unsigned int cpu_index);
+int cpu_phys_address_size(void);
 
 #define __cpu_driver __attribute__ ((used,__section__(".rodata.cpu_driver")))
 #ifndef __SIMPLE_DEVICE__