cpu: Provide a way to get the physical-address size

This concept exists on x86. Declare it as a generic function so that the
value can be accessed by UPL.

Signed-off-by: Simon Glass <sjg@chromium.org>
diff --git a/arch/x86/include/asm/cpu.h b/arch/x86/include/asm/cpu.h
index 8c1ef4c..fd389d4 100644
--- a/arch/x86/include/asm/cpu.h
+++ b/arch/x86/include/asm/cpu.h
@@ -284,15 +284,6 @@
  */
 u32 cpu_get_stepping(void);
 
-/**
- * cpu_phys_address_size() - Get the physical address size in bits
- *
- * This is 32 for older CPUs but newer ones may support 36.
- *
- * Return: address size (typically 32 or 36)
- */
-int cpu_phys_address_size(void);
-
 void board_final_init(void);
 void board_final_cleanup(void);
 
diff --git a/arch/x86/lib/bdinfo.c b/arch/x86/lib/bdinfo.c
index 2a78f57..bd2cf0b 100644
--- a/arch/x86/lib/bdinfo.c
+++ b/arch/x86/lib/bdinfo.c
@@ -5,6 +5,7 @@
  * Copyright 2021 Google LLC
  */
 
+#include <cpu.h>
 #include <efi.h>
 #include <init.h>
 #include <asm/cpu.h>