Remove unneeded include paths in PLAT_INCLUDES

Also, update platform_def.h guidelines about includes in the porting
guide.

Change-Id: I1ae338c9dd3242b309f6d53687ba2cb755d488c3
Signed-off-by: Antonio Nino Diaz <antonio.ninodiaz@arm.com>
diff --git a/plat/marvell/common/marvell_common.mk b/plat/marvell/common/marvell_common.mk
index fb6fbb5..a128261 100644
--- a/plat/marvell/common/marvell_common.mk
+++ b/plat/marvell/common/marvell_common.mk
@@ -22,8 +22,7 @@
 LLC_ENABLE			:= 1
 $(eval $(call add_define,LLC_ENABLE))
 
-PLAT_INCLUDES		+=	-I. -Iinclude/common -Iinclude/common/tbbr	\
-				-I$(MARVELL_PLAT_INCLUDE_BASE)/common	\
+PLAT_INCLUDES		+=	-I$(MARVELL_PLAT_INCLUDE_BASE)/common	\
 				-I$(MARVELL_PLAT_INCLUDE_BASE)/common/aarch64