rtc: at91rm9200: drop unused module alias

The driver only support OF probe so drop the unused platform module
alias.

Fixes: 288d9cf ("rtc: at91rm9200: use of_device_get_match_data()")
Signed-off-by: Johan Hovold <johan+linaro@kernel.org>
Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Link: https://lore.kernel.org/r/20250423130318.31244-2-johan+linaro@kernel.org
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>

Author: jhovold

drivers/rtc/rtc-at91rm9200.c

@@ -654,4 +654,3 @@ module_platform_driver_probe(at91_rtc_driver, at91_rtc_probe);
 MODULE_AUTHOR("Rick Bronson");
 MODULE_DESCRIPTION("RTC driver for Atmel AT91RM9200");
 MODULE_LICENSE("GPL");
-MODULE_ALIAS("platform:at91_rtc");