pc87360: Delete sysfs files on device deletion

Add 4 explicit attribute groups for the 5 sensor types:
voltage (in), therm, temp, and fan & pwm (together in one group).
Use sysfs_remove_group() to drop them, but keeps the existing
startup code, which calls device_create_file in loops.
Signed-off-by: Jim Cromie <jim.cromie@gmail.com>
Signed-off-by: Jean Delvare <khali@linux-fr.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>