rtc: isl1208: Fix incorrect logic in isl1208_set_xtoscb()

The XTOSCB bit is not bit 0, but xtosb_val is either 0 or 1. If it is 1,
test will never succeed. Fix this issue by using double negation.

While at it, remove unnecessary blank line from probe().

Reported-by: Pavel Machek <[e-mail]>
Closes: https://lore.kernel.org/all/[e-mail]/
Signed-off-by: Biju Das <[e-mail]>
Reviewed-by: Pavel Machek <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: Alexandre Belloni <[e-mail]>

drivers/rtc/rtc-isl1208.c

···
 static int isl1208_set_xtoscb(struct i2c_client *client, int sr, int xtosb_val)
 {
 	/* Do nothing if bit is already set to desired value */
-	if ((sr & ISL1208_REG_SR_XTOSCB) == xtosb_val)
+	if (!!(sr & ISL1208_REG_SR_XTOSCB) == xtosb_val)
 		return 0;
 
 	if (xtosb_val)
···
 		rc = isl1208_setup_irq(client, client->irq);
 		if (rc)
 			return rc;
-
 	} else {
 		clear_bit(RTC_FEATURE_UPDATE_INTERRUPT, isl1208->rtc->features);
 	}