rtc: at91sam9: Set name of regmap_config

We are now allowing to register debugfs without a valid device, and not
having a valid name will end up using "dummy*" to create debugfs dir.
Signed-off-by: Jeffy Chen <jeffy.chen@rock-chips.com>
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>

drivers/rtc/rtc-at91sam9.c

@@ -349,6 +349,7 @@ static const struct rtc_class_ops at91_rtc_ops = {
 };
 
 static const struct regmap_config gpbr_regmap_config = {
+	.name = "gpbr",
 	.reg_bits = 32,
 	.val_bits = 32,
 	.reg_stride = 4,