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>

arch/arm/include/asm/ti-common/ti-aemif.h

@@ -16,6 +16,7 @@
 #define AEMIF_PRESERVE             -1
 
 struct aemif_config {
+	void *base;
 	unsigned mode;
 	unsigned select_strobe;
 	unsigned extend_wait;