memory: Move TI_AEMIF config to KCONFIG

Not all Keystone2 devices has AEMIF NAND controller. So adding Kconfig
entry for CONFIG_TI_AEMIF and enabling it in respective defconfigs on
platforms with AEMIF controller.

Reported-by: Nishanth Menon <nm@ti.com>
Signed-off-by: Lokesh Vutla <lokeshvutla@ti.com>
Reviewed-by: Tom Rini <trini@konsulko.com>

drivers/memory/Kconfig

@@ -0,0 +1,18 @@
+#
+# Memory devices
+#
+
+menu "Memory Controller drivers"
+
+config TI_AEMIF
+	tristate "Texas Instruments AEMIF driver"
+	depends on ARCH_KEYSTONE
+	help
+	  This driver is for the AEMIF module available in Texas Instruments
+	  SoCs. AEMIF stands for Asynchronous External Memory Interface and
+	  is intended to provide a glue-less interface to a variety of
+	  asynchronuous memory devices like ASRAM, NOR and NAND memory. A total
+	  of 256M bytes of any of these memories can be accessed at a given
+	  time via four chip selects with 64M byte access per chip select.
+
+endmenu