hwmon: (lm70) Allow 4wire SPI bus with LM70

Removing the 3wire limitation on LM70 as the component also allows
operation on 4wire SPI bus
Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>

Documentation/hwmon/lm70

@@ -31,9 +31,8 @@ As a real (in-tree) example of this "SPI protocol driver" interfacing
 with a "SPI master controller driver", see drivers/spi/spi_lm70llp.c
 and its associated documentation.
 
-The TMP121/TMP123 are very similar; main differences are 4 wire SPI inter-
-face (read only) and 13-bit temperature data (0.0625 degrees celsius reso-
-lution).
+The TMP121/TMP123 are very similar; main difference is 13-bit temperature
+data (0.0625 degrees celsius resolution).
 
 Thanks to
 ---------

drivers/hwmon/lm70.c

@@ -143,10 +143,6 @@ static int __devinit lm70_probe(struct spi_device *spi)
 	if (spi->mode & (SPI_CPOL | SPI_CPHA))
 		return -EINVAL;
 
-	/* 3-wire link (shared SI/SO) for LM70 */
-	if (chip == LM70_CHIP_LM70 && !(spi->mode & SPI_3WIRE))
-		return -EINVAL;
-
 	/* NOTE:  we assume 8-bit words, and convert to 16 bits manually */
 
 	p_lm70 = devm_kzalloc(&spi->dev, sizeof(*p_lm70), GFP_KERNEL);