plat/arm: Sanitise includes

Use full include paths like it is done for common includes.

This cleanup was started in commit d40e0e08283a ("Sanitise includes
across codebase"), but it only cleaned common files and drivers. This
patch does the same to Arm platforms.

Change-Id: If982e6450bbe84dceb56d464e282bcf5d6d9ab9b
Signed-off-by: Antonio Nino Diaz <antonio.ninodiaz@arm.com>
diff --git a/plat/arm/css/common/css_common.mk b/plat/arm/css/common/css_common.mk
index ca1edab..0795306 100644
--- a/plat/arm/css/common/css_common.mk
+++ b/plat/arm/css/common/css_common.mk
@@ -11,8 +11,7 @@
 # By default, SCMI driver is disabled for CSS platforms
 CSS_USE_SCMI_SDS_DRIVER	?=	0
 
-PLAT_INCLUDES		+=	-Iinclude/plat/arm/css/common			\
-				-Iinclude/plat/arm/css/common/aarch64
+PLAT_INCLUDES		+=	-Iinclude/plat/arm/css/common/aarch64
 
 
 PLAT_BL_COMMON_SOURCES	+=	plat/arm/css/common/${ARCH}/css_helpers.S