We need "ret" to be unsigned for the error handling to work.  The
signedness of "i" and "n" don't matter but qspi_set_send_trigger()
returns an int so I've changed them to int as well.
Fixes: 4b6fe3edcbba ('spi: Using Trigger number to transmit/receive data')
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Mark Brown <broonie@kernel.org>
 static int qspi_trigger_transfer_out_int(struct rspi_data *rspi, const u8 *tx,
                                        u8 *rx, unsigned int len)
 {
-       unsigned int i, n, ret;
+       int i, n, ret;
        int error;
 
        while (len > 0) {