[RFT] powerpc/boot: Fix missing crc32poly.h when building with KERNEL_XZ

[Krzysztof Kozlowski]

After commit faa16bc404d7 ("lib: Use existing define with
polynomial") the lib/xz/xz_crc32.c includes a header from include/linux
directory thus any other user of this code should define proper include
path.

This fixes the build error on powerpc with CONFIG_KERNEL_XZ:

    In file included from ../arch/powerpc/boot/../../../lib/decompress_unxz.c:233:0,
                     from ../arch/powerpc/boot/decompress.c:42:
    ../arch/powerpc/boot/../../../lib/xz/xz_crc32.c:18:29: fatal error: linux/crc32poly.h: No such file or directory

Reported-by: Michal Kubecek <mkubecek@xxxxxxx>
Fixes: faa16bc404d7 ("lib: Use existing define with polynomial")
Signed-off-by: Krzysztof Kozlowski <krzk@xxxxxxxxxx>

---

Only compile tested.
---
 arch/powerpc/boot/Makefile | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/powerpc/boot/Makefile b/arch/powerpc/boot/Makefile
index 0fb96c26136f..ba4182fb185d 100644
--- a/arch/powerpc/boot/Makefile
+++ b/arch/powerpc/boot/Makefile
@@ -63,7 +63,7 @@ ifeq ($(call cc-option-yn, -fstack-protector),y)
 BOOTCFLAGS	+= -fno-stack-protector
 endif
 
-BOOTCFLAGS	+= -I$(objtree)/$(obj) -I$(srctree)/$(obj)
+BOOTCFLAGS	+= -I$(objtree)/$(obj) -I$(srctree)/$(obj) -I$(srctree)/include
 
 DTC_FLAGS	?= -p 1024
 
-- 
2.7.4