x86: Correct a build warning in x86 tables

There is a build warning for three x86 boards since
write_smbios_table_wrapper() is not used. Fix it.

Fixes: e824cf3f (smbios: Allow compilation on 64bit systems)
Signed-off-by: Simon Glass <sjg@chromium.org>
Signed-off-by: Alexander Graf <agraf@suse.de>

arch/x86/lib/tables.c

@@ -12,10 +12,12 @@
 #include <asm/acpi_table.h>
 #include <asm/coreboot_tables.h>
 
+#ifdef CONFIG_GENERATE_SMBIOS_TABLE
 static u32 write_smbios_table_wrapper(u32 addr)
 {
 	return write_smbios_table(addr);
 }
+#endif
 
 /**
  * Function prototype to write a specific configuration table