spi: nxp-fspi: Ensure width is respected in spi-mem operations

Make use of a core helper to ensure the desired width is respected
when calling spi-mem operators.

Otherwise only the SPI controller will be matched with the flash chip,
which might lead to wrong widths. Also consider the width specified by
the user in the device tree.

Fixes: a5356aef ("spi: spi-mem: Add driver for NXP FlexSPI controller")
Signed-off-by: Michael Walle <michael@walle.cc>
Link: https://lore.kernel.org/r/20191211195730.26794-1-michael@walle.ccSigned-off-by: Mark Brown <broonie@kernel.org>

drivers/spi/spi-nxp-fspi.c

@@ -439,7 +439,7 @@ static bool nxp_fspi_supports_op(struct spi_mem *mem,
 	    op->data.nbytes > f->devtype_data->txfifo)
 		return false;
 
-	return true;
+	return spi_mem_default_supports_op(mem, op);
 }
 
 /* Instead of busy looping invoke readl_poll_timeout functionality. */