selftests: vDSO - fix to exclude x86 test on non-x86 platforms

Fix to exclude vdso_standalone_test_x86 test from building on non-x86
platforms. In addition, fix it to use TEST_GEN_PROGS which is the right
variable to use for generated programs. TEST_PROGS is for shell scripts.
Signed-off-by: Shuah Khan (Samsung OSG) <shuah@kernel.org>

tools/testing/selftests/vDSO/Makefile

 # SPDX-License-Identifier: GPL-2.0
 include ../lib.mk
 
+uname_M := $(shell uname -m 2>/dev/null || echo not)
+ARCH ?= $(shell echo $(uname_M) | sed -e s/i.86/x86/ -e s/x86_64/x86/)
+
+TEST_GEN_PROGS := $(OUTPUT)/vdso_test
+ifeq ($(ARCH),x86)
+TEST_GEN_PROGS += $(OUTPUT)/vdso_standalone_test_x86
+endif
+
 ifndef CROSS_COMPILE
 CFLAGS := -std=gnu99
 CFLAGS_vdso_standalone_test_x86 := -nostdlib -fno-asynchronous-unwind-tables -fno-stack-protector
@@ -8,14 +16,11 @@ ifeq ($(CONFIG_X86_32),y)
 LDLIBS += -lgcc_s
 endif
 
-TEST_PROGS := $(OUTPUT)/vdso_test $(OUTPUT)/vdso_standalone_test_x86
-
-all: $(TEST_PROGS)
+all: $(TEST_GEN_PROGS)
 $(OUTPUT)/vdso_test: parse_vdso.c vdso_test.c
 $(OUTPUT)/vdso_standalone_test_x86: vdso_standalone_test_x86.c parse_vdso.c
 	$(CC) $(CFLAGS) $(CFLAGS_vdso_standalone_test_x86) \
 		vdso_standalone_test_x86.c parse_vdso.c \
 		-o $@
 
-EXTRA_CLEAN := $(TEST_PROGS)
 endif