Split CSS makefile for sp_min on Juno

This patch factors out common files required for sp_min for all CSS
platforms from the JUNO specific makefile to a the new `css_sp_min.mk`
makefile. This also allows the common build options that affect CSS
platforms to be configured in a central makefile for sp_min.

Change-Id: Ida952d8833b1aa5eda77ae0a6664a4632aeab24c
Signed-off-by: Soby Mathew <soby.mathew@arm.com>

plat/arm/board/juno/sp_min/sp_min-juno.mk

@@ -9,14 +9,10 @@ BL32_SOURCES	+=	lib/cpus/aarch32/cortex_a53.S		\
 			lib/cpus/aarch32/cortex_a57.S		\
 			lib/cpus/aarch32/cortex_a72.S		\
 			plat/arm/board/juno/juno_topology.c	\
-			plat/arm/css/common/css_pm.c		\
-			plat/arm/css/common/css_topology.c	\
 			plat/arm/soc/common/soc_css_security.c	\
-			plat/arm/css/drivers/scp/css_pm_scpi.c	\
-			plat/arm/css/drivers/scpi/css_mhu.c	\
-			plat/arm/css/drivers/scpi/css_scpi.c	\
 			${JUNO_GIC_SOURCES}			\
 			${JUNO_INTERCONNECT_SOURCES}		\
 			${JUNO_SECURITY_SOURCES}
 
 include plat/arm/common/sp_min/arm_sp_min.mk
+include plat/arm/css/common/sp_min/css_sp_min.mk

plat/arm/css/common/sp_min/css_sp_min.mk

+#
+# Copyright (c) 2017, ARM Limited and Contributors. All rights reserved.
+#
+# SPDX-License-Identifier: BSD-3-Clause
+#
+
+# SP MIN source files common to CSS platforms
+BL32_SOURCES		+=	plat/arm/css/common/css_pm.c			\
+				plat/arm/css/common/css_topology.c
+
+ifeq (${CSS_USE_SCMI_DRIVER},0)
+BL32_SOURCES		+=	plat/arm/css/drivers/scp/css_pm_scpi.c		\
+				plat/arm/css/drivers/scpi/css_mhu.c		\
+				plat/arm/css/drivers/scpi/css_scpi.c
+else
+BL32_SOURCES		+=	plat/arm/css/drivers/scp/css_pm_scmi.c		\
+				plat/arm/css/drivers/scmi/scmi_common.c		\
+				plat/arm/css/drivers/scmi/scmi_pwr_dmn_proto.c	\
+				plat/arm/css/drivers/scmi/scmi_sys_pwr_proto.c
+endif