dm: rtc: uclass: Add flag to control sequence numbering

RTCs are using aliases for sequences. That's why enable
DM_UC_FLAG_SEQ_ALIAS for exact RTC indentification.
The same flag is used by a lot of other uclasses like mmc, pci, serial,
spi, timer, tpm, etc.

Signed-off-by: Michal Simek <michal.simek@xilinx.com>
diff --git a/drivers/rtc/rtc-uclass.c b/drivers/rtc/rtc-uclass.c
index be6a2dd..321b873 100644
--- a/drivers/rtc/rtc-uclass.c
+++ b/drivers/rtc/rtc-uclass.c
@@ -176,6 +176,7 @@
 UCLASS_DRIVER(rtc) = {
 	.name		= "rtc",
 	.id		= UCLASS_RTC,
+	.flags		= DM_UC_FLAG_SEQ_ALIAS,
 #if !CONFIG_IS_ENABLED(OF_PLATDATA)
 	.post_bind	= dm_scan_fdt_dev,
 #endif