ext4: Only advertise encrypted_casefold when encryption and unicode are enabled

Encrypted casefolding is only supported when both encryption and
casefolding are both enabled in the config.

Fixes: 471fbbe ("ext4: handle casefolding with encryption")
Cc: stable@vger.kernel.org # 5.13+
Signed-off-by: Daniel Rosenberg <drosen@google.com>
Link: https://lore.kernel.org/r/20210603094849.314342-1-drosen@google.com
Signed-off-by: Theodore Ts'o <tytso@mit.edu>

Author: drosen-google

fs/ext4/sysfs.c

@@ -315,7 +315,9 @@ EXT4_ATTR_FEATURE(verity);
 #endif
 EXT4_ATTR_FEATURE(metadata_csum_seed);
 EXT4_ATTR_FEATURE(fast_commit);
+#if defined(CONFIG_UNICODE) && defined(CONFIG_FS_ENCRYPTION)
 EXT4_ATTR_FEATURE(encrypted_casefold);
+#endif
 
 static struct attribute *ext4_feat_attrs[] = {
 	ATTR_LIST(lazy_itable_init),
@@ -333,7 +335,9 @@ static struct attribute *ext4_feat_attrs[] = {
 #endif
 	ATTR_LIST(metadata_csum_seed),
 	ATTR_LIST(fast_commit),
+#if defined(CONFIG_UNICODE) && defined(CONFIG_FS_ENCRYPTION)
 	ATTR_LIST(encrypted_casefold),
+#endif
 	NULL,
 };
 ATTRIBUTE_GROUPS(ext4_feat);