ia64: fix sn to add include files using EXTRA_CFLAGS

Changing the global CPPFLAGS is not the recommended way
to add additional include dirs.
Changed to use EXTRA_CFLAGS.
Signed-off-by: Sam Ravnborg <sam@ravnborg.org>
Acked-by: Jes Sorensen <jes@sgi.com>

arch/ia64/sn/kernel/Makefile

@@ -7,7 +7,7 @@
 # Copyright (C) 1999,2001-2006 Silicon Graphics, Inc.  All Rights Reserved.
 #
 
-CPPFLAGS += -I$(srctree)/arch/ia64/sn/include
+EXTRA_CFLAGS += -Iarch/ia64/sn/include
 
 obj-y				+= setup.o bte.o bte_error.o irq.o mca.o idle.o \
 				   huberror.o io_acpi_init.o io_common.o \

arch/ia64/sn/kernel/sn2/Makefile

@@ -9,7 +9,7 @@
 # sn2 specific kernel files
 #
 
-CPPFLAGS += -I$(srctree)/arch/ia64/sn/include
+EXTRA_CFLAGS += -Iarch/ia64/sn/include
 
 obj-y += cache.o io.o ptc_deadlock.o sn2_smp.o sn_proc_fs.o \
 	 prominfo_proc.o timer.o timer_interrupt.o sn_hwperf.o

arch/ia64/sn/pci/Makefile

@@ -7,6 +7,6 @@
 #
 # Makefile for the sn pci general routines.
 
-CPPFLAGS += -I$(srctree)/arch/ia64/sn/include
+EXTRA_CFLAGS += -Iarch/ia64/sn/include
 
 obj-y := pci_dma.o tioca_provider.o tioce_provider.o pcibr/

arch/ia64/sn/pci/pcibr/Makefile

@@ -7,7 +7,7 @@
 #
 # Makefile for the sn2 io routines.
 
-CPPFLAGS += -I$(srctree)/arch/ia64/sn/include
+EXTRA_CFLAGS += -Iarch/ia64/sn/include
 
 obj-y				+=  pcibr_dma.o pcibr_reg.o \
 				    pcibr_ate.o pcibr_provider.o