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/adcxx.c b/drivers/hwmon/adcxx.c
index ceb24a3..a3d3183 100644
--- a/drivers/hwmon/adcxx.c
+++ b/drivers/hwmon/adcxx.c
@@ -248,18 +248,7 @@
 	.remove	= __devexit_p(adcxx_remove),
 };
 
-static int __init init_adcxx(void)
-{
-	return spi_register_driver(&adcxx_driver);
-}
-
-static void __exit exit_adcxx(void)
-{
-	spi_unregister_driver(&adcxx_driver);
-}
-
-module_init(init_adcxx);
-module_exit(exit_adcxx);
+module_spi_driver(adcxx_driver);
 
 MODULE_AUTHOR("Marc Pignat");
 MODULE_DESCRIPTION("National Semiconductor adcxx8sxxx Linux driver");