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 <axel.lin@gmail.com>
Signed-off-by: Anton Vorontsov <cbouatmailru@gmail.com>
diff --git a/drivers/power/z2_battery.c b/drivers/power/z2_battery.c
index e5ed52d..81304c0 100644
--- a/drivers/power/z2_battery.c
+++ b/drivers/power/z2_battery.c
@@ -293,6 +293,7 @@
 	{ "aer915", 0 },
 	{ }
 };
+MODULE_DEVICE_TABLE(i2c, z2_batt_id);
 
 static struct i2c_driver z2_batt_driver = {
 	.driver	= {