hwmon: convert drivers/hwmon/* to use module_spi_driver()

This patch converts the drivers in drivers/hwmon/* to use the
module_spi_driver() macro which makes the code smaller and a bit simpler.

Signed-off-by: Axel Lin <axel.lin@gmail.com>
Cc: Sonic Zhang <sonic.zhang@analog.com>
Cc: Marc Pignat <marc.pignat@hevs.ch>
Cc: Paul Thomas <pthomas8589@gmail.com>
Cc: Eric Miao <eric.y.miao@gmail.com>
Acked-by: Sonic Zhang <sonic.zhang@analog.com>
Signed-off-by: Guenter Roeck <guenter.roeck@ericsson.com>
diff --git a/drivers/hwmon/ads7871.c b/drivers/hwmon/ads7871.c
index 04450f8..11a5f5f 100644
--- a/drivers/hwmon/ads7871.c
+++ b/drivers/hwmon/ads7871.c
@@ -234,18 +234,7 @@
 	.remove = __devexit_p(ads7871_remove),
 };
 
-static int __init ads7871_init(void)
-{
-	return spi_register_driver(&ads7871_driver);
-}
-
-static void __exit ads7871_exit(void)
-{
-	spi_unregister_driver(&ads7871_driver);
-}
-
-module_init(ads7871_init);
-module_exit(ads7871_exit);
+module_spi_driver(ads7871_driver);
 
 MODULE_AUTHOR("Paul Thomas <pthomas8589@gmail.com>");
 MODULE_DESCRIPTION("TI ADS7871 A/D driver");