Fix key-size descriptions

For compatibility reasons, cryptsetup uses key size in BITS
while integritysetup in BYTES.

The help is confusing here, this patch fixes it.

Thanks Daniel Tang for notification.

src/utils_reencrypt.c

@@ -1914,6 +1914,7 @@ static int reencrypt_luks2_init(struct crypt_device *cd, const char *data_device
 			new_key_size = ARG_UINT32(OPT_NEW_KEY_SIZE_ID);
 
 		if (new_key_size || new_cipher)
+			/* This will convert new key size to bytes from bits */
 			new_key_size = get_adjusted_key_size(cipher, mode, new_key_size,
 							 DEFAULT_LUKS1_KEYBITS, 0);
 		else