Use sanitized headers in data-ipa-cfg-mgr makefiles

Change-Id: I43450840cb3fc8c288475c8ecb352dd3b4e6eafb
diff --git a/ipanat/src/Makefile.am b/ipanat/src/Makefile.am
index cf9fc3f..f8b775c 100644
--- a/ipanat/src/Makefile.am
+++ b/ipanat/src/Makefile.am
@@ -1,5 +1,5 @@
 AM_CFLAGS = -Wall -Wundef -Wstrict-prototypes -Wno-trigraphs
-AM_CFLAGS += -I./../inc -I$(WORKSPACE)/kernel/include
+AM_CFLAGS += -I./../inc
 
 c_sources   = ipa_nat_drv.c \
               ipa_nat_drvi.c \