ARM: dts: aspeed: rainier: Add gpio-keys-polled for fans

Add a gpio-keys-polled section to the Rainier device tree for the fan
presence signals on the PCA9552 I2C device on bus 7.

Signed-off-by: Brandon Wyman <bjwyman@gmail.com>
Signed-off-by: Matthew Barth <msbarth@linux.ibm.com>
Signed-off-by: Eddie James <eajames@linux.ibm.com>
Link: https://lore.kernel.org/r/20210329150020.13632-4-eajames@linux.ibm.com


Signed-off-by: Joel Stanley <joel@jms.id.au>