z2_battery: Add MODULE_DEVICE_TABLE

The device table is required to load modules based on modaliases.
After adding the MODULE_DEVICE_TABLE, below entry will be added to
modules.alias:
alias i2c:aer915 z2_battery

Signed-off-by: Axel Lin <[e-mail]>
Signed-off-by: Anton Vorontsov <[e-mail]>

drivers/power/z2_battery.c

···
 	{ "aer915", 0 },
 	{ }
 };
+MODULE_DEVICE_TABLE(i2c, z2_batt_id);
 
 static struct i2c_driver z2_batt_driver = {
 	.driver	= {