power: supply: bq24190_charger: Fix irq trigger to IRQF_TRIGGER_FALLING

The interrupt signal is TRIGGER_FALLING. This is is specified in the
data sheet PIN FUNCTIONS: "The INT pin sends active low, 256us
pulse to host to report charger device status and fault."

Also the direction can be seen in the data sheet Figure 37 "BQ24190
with D+/D- Detection and USB On-The-Go (OTG)" which shows a 10k
pull-up resistor installed for the sample configurations.

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>