iio: stx104: Utilize the module_isa_driver and max_num_isa_dev macros

The Apex Embedded Systems STX104 DAC drivers does not do anything
special in module init/exit. This patch eliminates the module init/exit
boilerplate code by utilizing the module_isa_driver macro.

Additionally, the max_num_isa_dev macro is utilized to simplify the
determination of maximum possible STX104 devices in the system.

Cc: Jonathan Cameron <[e-mail]>
Cc: Hartmut Knaack <[e-mail]>
Cc: Lars-Peter Clausen <[e-mail]>
Cc: Peter Meerwald <[e-mail]>
Signed-off-by: William Breathitt Gray <[e-mail]>
Signed-off-by: Greg Kroah-Hartman <[e-mail]>

drivers/iio/dac/stx104.c

···
 }
 
 #define STX104_EXTENT 16
-/**
- * The highest base address possible for an ISA device is 0x3FF; this results in
- * 1024 possible base addresses. Dividing the number of possible base addresses
- * by the address extent taken by each device results in the maximum number of
- * devices on a system.
- */
-#define MAX_NUM_STX104 (1024 / STX104_EXTENT)
 
-static unsigned base[MAX_NUM_STX104];
-static unsigned num_stx104;
+static unsigned int base[max_num_isa_dev(STX104_EXTENT)];
+static unsigned int num_stx104;
 module_param_array(base, uint, &num_stx104, 0);
 MODULE_PARM_DESC(base, "Apex Embedded Systems STX104 base addresses");
 
···
 	}
 };
 
-static void __exit stx104_exit(void)
-{
-	isa_unregister_driver(&stx104_driver);
-}
-
-static int __init stx104_init(void)
-{
-	return isa_register_driver(&stx104_driver, num_stx104);
-}
-
-module_init(stx104_init);
-module_exit(stx104_exit);
+module_isa_driver(stx104_driver, num_stx104);
 
 MODULE_AUTHOR("William Breathitt Gray <[e-mail]>");
 MODULE_DESCRIPTION("Apex Embedded Systems STX104 DAC driver");