dm: memory: Introduce new uclass

Introduce UCLASS_MEMORY for future Memory Controller
device drivers.

Signed-off-by: Roger Quadros <rogerq@kernel.org>
Reviewed-by: Simon Glass <sjg@chromium.org>
diff --git a/drivers/memory/Makefile b/drivers/memory/Makefile
index fec52ef..b27f701 100644
--- a/drivers/memory/Makefile
+++ b/drivers/memory/Makefile
@@ -1,3 +1,5 @@
 
+obj-$(CONFIG_MEMORY) += memory-uclass.o
+obj-$(CONFIG_SANDBOX_MEMORY) += memory-sandbox.o
 obj-$(CONFIG_STM32_FMC2_EBI) += stm32-fmc2-ebi.o
 obj-$(CONFIG_TI_AEMIF) += ti-aemif.o