[PATCH] selftests: powerpc: Fix warning for security subdir

[Joel Stanley]

typing 'make' inside tools/testing/selftests/powerpc gave a build
warning:

BUILD_TARGET=tools/testing/selftests/powerpc/security; mkdir -p $BUILD_TARGET; make OUTPUT=$BUILD_TARGET -k -C security all
make[1]: Entering directory 'tools/testing/selftests/powerpc/security'
../../lib.mk:20: ../../../../scripts/subarch.include: No such file or directory
make[1]: *** No rule to make target '../../../../scripts/subarch.include'.
make[1]: Failed to remake makefile '../../../../scripts/subarch.include'.

The build is one level deeper than lib.mk thinks it is. Set top_srcdir
to set things straight.

Note that the test program is still built.

Signed-off-by: Joel Stanley <joel at jms.id.au>
---
 tools/testing/selftests/powerpc/security/Makefile | 1 +
 1 file changed, 1 insertion(+)

diff --git a/tools/testing/selftests/powerpc/security/Makefile b/tools/testing/selftests/powerpc/security/Makefile
index 44690f1bb26a..85861c46b445 100644
--- a/tools/testing/selftests/powerpc/security/Makefile
+++ b/tools/testing/selftests/powerpc/security/Makefile
@@ -1,6 +1,7 @@
 # SPDX-License-Identifier: GPL-2.0+
 
 TEST_GEN_PROGS := rfi_flush
+top_srcdir = ../../../../..
 
 CFLAGS += -I../../../../../usr/include
 
-- 
2.19.1