ext4: get rid of ext4_sb_has_crypto()

ext4_sb_has_crypto() just called through to ext4_has_feature_encrypt(),
and all callers except one were already using the latter.  So remove it
and switch its one caller to ext4_has_feature_encrypt().

Signed-off-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
diff --git a/fs/ext4/ioctl.c b/fs/ext4/ioctl.c
index 2faeb3c..560afe0 100644
--- a/fs/ext4/ioctl.c
+++ b/fs/ext4/ioctl.c
@@ -806,7 +806,7 @@ long ext4_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
 		struct ext4_sb_info *sbi = EXT4_SB(sb);
 		handle_t *handle;
 
-		if (!ext4_sb_has_crypto(sb))
+		if (!ext4_has_feature_encrypt(sb))
 			return -EOPNOTSUPP;
 		if (uuid_is_zero(sbi->s_es->s_encrypt_pw_salt)) {
 			err = mnt_want_write_file(filp);