rtc: cpcap: drop unused module alias

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

Fixes: dd3bf50b ("rtc: cpcap: new rtc driver")
Signed-off-by: Johan Hovold <johan+linaro@kernel.org>
Reviewed-by: Sebastian Reichel <sebastian.reichel@collabora.com>
Link: https://lore.kernel.org/r/20250423130318.31244-3-johan+linaro@kernel.org


Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>