selftests/futex: don't redefine .PHONY targets (all, clean)

The .PHONY targets "all" and "clean" are both already defined in the
file that is included in the very next line:

../lib.mk.

Remove this duplicate code.

Reviewed-by: Davidlohr Bueso <[e-mail]>
Signed-off-by: John Hubbard <[e-mail]>
Signed-off-by: Shuah Khan <[e-mail]>

tools/testing/selftests/futex/Makefile

···
 
 TEST_PROGS := run.sh
 
-.PHONY: all clean
-
 include ../lib.mk
 
 all: