Makefile: delete unnecessary CPPFLAGS settings

Signed-off-by: Masahiro Yamada <yamada.m@jp.panasonic.com>
diff --git a/board/freescale/common/p_corenet/Makefile b/board/freescale/common/p_corenet/Makefile
index 889c493..1f399d2 100644
--- a/board/freescale/common/p_corenet/Makefile
+++ b/board/freescale/common/p_corenet/Makefile
@@ -5,8 +5,6 @@
 # SPDX-License-Identifier:	GPL-2.0+
 #
 
-CPPFLAGS += -I$(TOPDIR)
-
 obj-y			+= law.o
 obj-$(CONFIG_PCI)	+= pci.o
 obj-y			+= tlb.o
diff --git a/common/Makefile b/common/Makefile
index 74404be..d12cba5 100644
--- a/common/Makefile
+++ b/common/Makefile
@@ -230,8 +230,6 @@
 obj-y += memsize.o
 obj-y += stdio.o
 
-CPPFLAGS += -I..
-
 $(obj)env_embedded.o: $(src)env_embedded.c
 	$(CC) $(AFLAGS) -Wa,--no-warn \
 		-DENV_CRC=$(shell $(obj)../tools/envcrc) \