cmd: date: Handle -ENOSYS return from dm_rtc_reset()

In case dm_rtc_reset() returns -ENOSYS, it means the .reset callback
in RTC driver is not implemented, likely because the callback is not
needed. Handle the -ENOSYS return code as success and proceed, else
the 'date reset' invocation incorrectly prints a bogus warning:
"## Failed to set date after RTC reset".

Signed-off-by: Marek Vasut <marex@nabladev.com>
Reviewed-by: Simon Glass <sjg@chromium.org>

cmd/date.c

@@ -44,7 +44,7 @@ static int do_date(struct cmd_tbl *cmdtp, int flag, int argc,
 		if (strcmp(argv[1],"reset") == 0) {
 			puts ("Reset RTC...\n");
 			rcode = dm_rtc_reset(dev);
-			if (!rcode)
+			if (!rcode || rcode == -ENOSYS)
 				rcode = dm_rtc_set(dev, &default_tm);
 			if (rcode)
 				puts("## Failed to set date after RTC reset\n");