selftests/powerpc: Fix Makefiles for headers_install change

[Michael Ellerman]

On Fri, 2018-09-28 at 05:43:23 UTC, Michael Ellerman wrote:
> Commit b2d35fa5fc80 ("selftests: add headers_install to lib.mk")
> introduced a requirement that Makefiles more than one level below the
> selftests directory need to define top_srcdir, but it didn't update
> any of the powerpc Makefiles.
> 
> This broke building all the powerpc selftests with eg:
> 
>   make[1]: Entering directory '/src/linux/tools/testing/selftests/powerpc'
>   BUILD_TARGET=/src/linux/tools/testing/selftests/powerpc/alignment; mkdir -p $BUILD_TARGET; make OUTPUT=$BUILD_TARGET -k -C alignment all
>   make[2]: Entering directory '/src/linux/tools/testing/selftests/powerpc/alignment'
>   ../../lib.mk:20: ../../../../scripts/subarch.include: No such file or directory
>   make[2]: *** No rule to make target '../../../../scripts/subarch.include'.
>   make[2]: Failed to remake makefile '../../../../scripts/subarch.include'.
>   Makefile:38: recipe for target 'alignment' failed
> 
> Fix it by setting top_srcdir in the affected Makefiles.
> 
> Fixes: b2d35fa5fc80 ("selftests: add headers_install to lib.mk")
> Signed-off-by: Michael Ellerman <mpe at ellerman.id.au>

Applied to powerpc fixes.

https://git.kernel.org/powerpc/c/7e0cf1c983b5b24426d130fd949a05

cheers