memory: ti-aemif: Make AEMIF driver architecture agnostic

AEMIF controller is present on other SoCs than the Keystone ones.

Remove Keystone specificities from the driver to be able to use it from
other architectures.
Adapt the ks2_evm/board.c to fit the new driver.

Signed-off-by: Bastien Curutchet <bastien.curutchet@bootlin.com>
Reviewed-by: Tom Rini <trini@konsulko.com>
3 files changed