refactor(st-ddr): reorganize generic and specific elements

stm32mp_ddrctl structure contains DDRCTRL registers definitions.
stm32mp_ddr_info contains general DDR information extracted from DT.
stm32mp_ddr_size moves to the generic side.
stm32mp1_ddr_priv contains platform private data.

stm32mp_ddr_dt_get_info() and stm32mp_ddr_dt_get_param() allow to
retrieve data from DT. They are located in new generic c/h files in
which stm32mp_ddr_param structure is declared. Platform makefile
is updated.

Adapt driver with this new classification.

Signed-off-by: Nicolas Le Bayon <nicolas.le.bayon@st.com>
Change-Id: I4187376c9fff1a30e7a94407d188391547107997
diff --git a/plat/st/stm32mp1/platform.mk b/plat/st/stm32mp1/platform.mk
index 5462297..facc955 100644
--- a/plat/st/stm32mp1/platform.mk
+++ b/plat/st/stm32mp1/platform.mk
@@ -203,6 +203,7 @@
 				drivers/st/bsec/bsec.c					\
 				drivers/st/clk/stm32mp_clkfunc.c			\
 				drivers/st/clk/stm32mp1_clk.c				\
+				drivers/st/ddr/stm32mp_ddr.c				\
 				drivers/st/ddr/stm32mp1_ddr_helpers.c			\
 				drivers/st/gpio/stm32_gpio.c				\
 				drivers/st/i2c/stm32_i2c.c				\
@@ -296,7 +297,8 @@
 				plat/st/stm32mp1/stm32mp1_usb_dfu.c
 endif
 
-BL2_SOURCES		+=	drivers/st/ddr/stm32mp1_ddr.c				\
+BL2_SOURCES		+=	drivers/st/ddr/stm32mp_ram.c				\
+				drivers/st/ddr/stm32mp1_ddr.c				\
 				drivers/st/ddr/stm32mp1_ram.c
 
 BL2_SOURCES		+=	common/desc_image_load.c				\