selftests: remove useless TEST_DIRS

The TEST_DIRS was introduced in Commit e8c1d7cdf137 ("selftests: copy
TEST_DIRS to INSTALL_PATH") for coping a whole directory in ftrace.

After rsync(with -a) is introduced by Commit 900d65ee11aa ("selftests:
change install command to rsync"). Rsync could handle the directory
without the definition of TEST_DIRS.

This patch simply replace TEST_DIRS with TEST_FILES in ftrace and remove
the TEST_DIRS in tools/testing/selftest/lib.mk

Acked-by: Michael Ellerman <[e-mail]>
Signed-off-by: Bamvor Jian Zhang <[e-mail]>
Signed-off-by: Shuah Khan <[e-mail]>

tools/testing/selftests/ftrace/Makefile

···
 all:
 
 TEST_PROGS := ftracetest
-TEST_DIRS := test.d
+TEST_FILES := test.d
 
 include ../lib.mk
 

tools/testing/selftests/lib.mk

···
 define INSTALL_RULE
 	@if [ "X$(TEST_PROGS)$(TEST_PROGS_EXTENDED)$(TEST_FILES)" != "X" ]; then					\
 		mkdir -p ${INSTALL_PATH};										\
-		echo "rsync -a $(TEST_DIRS) $(TEST_PROGS) $(TEST_PROGS_EXTENDED) $(TEST_FILES) $(INSTALL_PATH)/";       \
-		rsync -a $(TEST_DIRS) $(TEST_PROGS) $(TEST_PROGS_EXTENDED) $(TEST_FILES) $(INSTALL_PATH)/;              \
+		echo "rsync -a $(TEST_PROGS) $(TEST_PROGS_EXTENDED) $(TEST_FILES) $(INSTALL_PATH)/";	\
+		rsync -a $(TEST_PROGS) $(TEST_PROGS_EXTENDED) $(TEST_FILES) $(INSTALL_PATH)/;		\
 	fi
 	@if [ "X$(TEST_GEN_PROGS)$(TEST_GEN_PROGS_EXTENDED)$(TEST_GEN_FILES)" != "X" ]; then					\
 		mkdir -p ${INSTALL_PATH};										\