power: supply: max17040: Do not enforce (incorrect) interrupt trigger type

Interrupt line can be configured on different hardware in different way,
even inverted.  Therefore driver should not enforce specific trigger
type - edge falling - but instead rely on Devicetree to configure it.

The Maxim 14577/77836 datasheets describe the interrupt line as active
low with a requirement of acknowledge from the CPU therefore the edge
falling is not correct.
Signed-off-by: Krzysztof Kozlowski <krzk@kernel.org>
Acked-by: Iskren Chernev <iskren.chernev@gmail.com>
Acked-by: Rob Herring <robh@kernel.org>
Signed-off-by: Sebastian Reichel <sebastian.reichel@collabora.com>

Documentation/devicetree/bindings/power/supply/maxim,max17040.yaml

@@ -89,7 +89,7 @@ examples:
         reg = <0x36>;
         maxim,alert-low-soc-level = <10>;
         interrupt-parent = <&gpio7>;
-        interrupts = <2 IRQ_TYPE_EDGE_FALLING>;
+        interrupts = <2 IRQ_TYPE_LEVEL_LOW>;
         wakeup-source;
       };
     };

drivers/power/supply/max17040_battery.c

@@ -361,12 +361,10 @@ static irqreturn_t max17040_thread_handler(int id, void *dev)
 static int max17040_enable_alert_irq(struct max17040_chip *chip)
 {
 	struct i2c_client *client = chip->client;
-	unsigned int flags;
 	int ret;
 
-	flags = IRQF_TRIGGER_FALLING | IRQF_ONESHOT;
 	ret = devm_request_threaded_irq(&client->dev, client->irq, NULL,
-					max17040_thread_handler, flags,
+					max17040_thread_handler, IRQF_ONESHOT,
 					chip->battery->desc->name, chip);
 
 	return ret;