We wrongly get uevents for bq24190-charger and bq24190-battery on every
register change.

Fix by checking the association with charger and battery before
emitting uevent(s).

Fixes: d7bf353f ("bq24190_charger: Add support for TI BQ24190 Battery Charger")
Signed-off-by: Liam Breck <kernel@networkimprov.net>
Acked-by: Mark Greer <mgreer@animalcreek.com>
Acked-by: Tony Lindgren <tony@atomide.com>
Signed-off-by: Sebastian Reichel <sre@kernel.org>