spi/ti-qspi: Fix return from mmap path

mmap resource requirement is only for memory mapped operations.
If the user does not populate mmap resource, dont call return,
instead we go on for normal spi mode operations.
Signed-off-by: NSourav Poddar <sourav.poddar@ti.com>
Signed-off-by: NMark Brown <broonie@linaro.org>

drivers/spi/spi-ti-qspi.c

@@ -461,7 +461,6 @@ static int ti_qspi_probe(struct platform_device *pdev)
 		if (res_mmap == NULL) {
 			dev_err(&pdev->dev,
 				"memory mapped resource not required\n");
-			return -ENODEV;
 		}
 	}