rtc: max31335: fix interrupt status reg

Fix the register value comparison in the `max31335_volatile_reg`
function for the interrupt status register.

MAX31335_STATUS1 macro definition corresponds to the actual
interrupt status register.

Fixes: dedaf03b99d6 ("rtc: max31335: add driver support")
Signed-off-by: Antoniu Miclaus <[e-mail]>
Reviewed-by: Nuno Sa <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: Alexandre Belloni <[e-mail]>

drivers/rtc/rtc-max31335.c

···
 		return true;
 
 	/* interrupt status register */
-	if (reg == MAX31335_INT_EN1_A1IE)
+	if (reg == MAX31335_STATUS1)
 		return true;
 
 	/* temperature registers */