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: 471fbbea7ff7 ("ext4: handle casefolding with encryption")
Cc: [e-mail] # 5.13+
Signed-off-by: Daniel Rosenberg <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: Theodore Ts'o <[e-mail]>

fs/ext4/sysfs.c

···
 #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),
···
 #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);