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/cpu/intel/haswell/romstage.c

@@ -18,6 +18,7 @@
 #include <cbfs.h>
 #include <console/console.h>
 #include <arch/cpu.h>
+#include <cpu/cpu.h>
 #include <cpu/x86/bist.h>
 #include <cpu/x86/msr.h>
 #include <cpu/x86/mtrr.h>