x86-64: Don't export init_level4_pgt

It's not used by any module, and i386 (as well as some other arches)
also doesn't export its equivalent (swapper_pg_dir).
Signed-off-by: NJan Beulich <jbeulich@novell.com>
LKML-Reference: <4BCF33BD020000780003B3E4@vpn.id2.novell.com>
Signed-off-by: NH. Peter Anvin <hpa@zytor.com>

arch/x86/kernel/x8664_ksyms_64.c

@@ -54,7 +54,6 @@ EXPORT_SYMBOL(memcpy);
 EXPORT_SYMBOL(__memcpy);
 
 EXPORT_SYMBOL(empty_zero_page);
-EXPORT_SYMBOL(init_level4_pgt);
 #ifndef CONFIG_PARAVIRT
 EXPORT_SYMBOL(native_load_gs_index);
 #endif