AArch32: Add SP_MIN support for JUNO

This patch adds support for SP_MIN on JUNO platform.
The changes include addition of AArch32 assembly files,
JUNO specific SP_MIN make file and miscellaneous changes
in ARM platform files to enable support for SP_MIN.

Change-Id: Id1303f422fc9b98b9362c757b1a4225a16fffc0b
Signed-off-by: Yatharth Kochar <yatharth.kochar@arm.com>
Signed-off-by: dp-arm <dimitris.papastamos@arm.com>
diff --git a/plat/arm/css/common/css_common.mk b/plat/arm/css/common/css_common.mk
index 7829e8b..24215a5 100644
--- a/plat/arm/css/common/css_common.mk
+++ b/plat/arm/css/common/css_common.mk
@@ -36,7 +36,7 @@
 				-Iinclude/plat/arm/css/common/aarch64
 
 
-PLAT_BL_COMMON_SOURCES	+=	plat/arm/css/common/aarch64/css_helpers.S
+PLAT_BL_COMMON_SOURCES	+=	plat/arm/css/common/${ARCH}/css_helpers.S
 
 BL1_SOURCES		+=	plat/arm/css/common/css_bl1_setup.c