spi: spi-gxp: BUG: Correct spi write return value

Bug fix to correct return value of gxp_spi_write function to zero.
Completion of succesful operation should return zero.

Fixes: 730bc8ba spi: spi-gxp: Add support for HPE GXP SoCs
Signed-off-by: Charles Kearney <charles.kearney@hpe.com>
Link: https://lore.kernel.org/r/20230920215339.4125856-2-charles.kearney@hpe.comSigned-off-by: Mark Brown <broonie@kernel.org>

drivers/spi/spi-gxp.c

@@ -194,7 +194,7 @@ static ssize_t gxp_spi_write(struct gxp_spi_chip *chip, const struct spi_mem_op
 		return ret;
 	}
 
-	return write_len;
+	return 0;
 }
 
 static int do_gxp_exec_mem_op(struct spi_mem *mem, const struct spi_mem_op *op)