power: supply: sbs-battery: Silence warning about unknown chemistry

Older variants of controller don't support reporting type of the battery.
Make warning message about unknown chemistry to be printed only once in
order to stop flooding kernel log with the message on each request of the
property. This patch fixes the noisy messages on Asus Transformer TF101.

Signed-off-by: Dmitry Osipenko <[email protected]>

drivers/power/supply/sbs-battery.c

@@ -814,7 +814,7 @@ static int sbs_get_chemistry(struct i2c_client *client,
 		val->intval = POWER_SUPPLY_TECHNOLOGY_UNKNOWN;
 
 	if (val->intval == POWER_SUPPLY_TECHNOLOGY_UNKNOWN)
-		dev_warn(&client->dev, "Unknown chemistry: %s\n", chemistry);
+		dev_warn_once(&client->dev, "Unknown chemistry: %s\n", chemistry);
 
 	return 0;
 }