rtc: bd70528: Avoid double error messaging when IRQ absent

Since the commit 7723f4c5 ("driver core: platform: Add an error message
to platform_get_irq*()") platform_get_irq() started issuing an error message.
Thus, there is no need to have the same in the driver.

Signed-off-by: Keyur Patel <iamkeyur96@gmail.com>
Link: https://lore.kernel.org/r/20200321180838.12729-1-iamkeyur96@gmail.com


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