cpu/x86/smm: Promote smm_memory_map()

Change-Id: I909e9b5fead317928d3513a677cfab25e3c42f64
Signed-off-by: Kyösti Mälkki <kyosti.malkki@gmail.com>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/34792
Reviewed-by: Aaron Durbin <adurbin@chromium.org>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>

src/include/cpu/x86/smm.h

@@ -160,4 +160,7 @@ enum {
  * 0 on success, < 0 on failure. */
 int smm_subregion(int sub, uintptr_t *start, size_t *size);
 
+/* Print the SMM memory layout on console. */
+void smm_list_regions(void);
+
 #endif /* CPU_X86_SMM_H */