powerpc: Export powerpc_debugfs_root

Kernel modules should be able to place their debug output inside our
powerpc debugfs directory.
Signed-off-by: NAnton Blanchard <anton@samba.org>
Signed-off-by: NPaul Mackerras <paulus@samba.org>

arch/powerpc/kernel/setup-common.c

@@ -660,6 +660,7 @@ late_initcall(check_cache_coherency);
 
 #ifdef CONFIG_DEBUG_FS
 struct dentry *powerpc_debugfs_root;
+EXPORT_SYMBOL(powerpc_debugfs_root);
 
 static int powerpc_debugfs_init(void)
 {