[PATCH] selftests/kexec: don't fail the build on other architectures

[Sasha Levin <sashal@kernel.org>]

The kexec tests are only built for x86 and ppc64le. On other
architectures the Makefile defines no rules, so building or installing
the suite fails:

  make[1]: *** No targets.  Stop.

Give the Makefile empty targets there, as sparc64 and
drivers/s390x/uvdevice do, so that the suite builds and installs
nothing.

Fixes: a802ed0dd9c2 ("selftests/ima: kexec_load syscall test")
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
Found with KernelCI-style TuxMake builds that record per-suite results
with KSFT_BUILD_REPORT. x86_64 builds don't change, and arm64 and arm
builds now succeed without installing anything.

With ARCH=powerpc, as passed by the kernel's kselftest targets and by
CI, the ppc64le check doesn't match either, so the tests are only built
on powerpc when ARCH is taken from uname -m. This patch leaves that
alone.

 tools/testing/selftests/kexec/Makefile | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/tools/testing/selftests/kexec/Makefile b/tools/testing/selftests/kexec/Makefile
index 874cfdd3b75b3..11b30d49a7f23 100644
--- a/tools/testing/selftests/kexec/Makefile
+++ b/tools/testing/selftests/kexec/Makefile
@@ -17,4 +17,8 @@ endif
 
 include ../lib.mk
 
+else
+nothing:
+.PHONY: all clean run_tests install
+.SILENT:
 endif
-- 
2.53.0