build: remove pointless condition

$(STRIP) always expands to something, because it is one of the commands
in the BRIEF list. This renders the condition pointless.
Signed-off-by: Ingo Brückl <ib@wupperonline.de>
Signed-off-by: Derek Buitenhuis <derek.buitenhuis@gmail.com>

library.mak

@@ -25,7 +25,7 @@ $(SUBDIR)%-test.i: $(SUBDIR)%.c
 $(SUBDIR)x86/%.o: $(SUBDIR)x86/%.asm
 	$(DEPYASM) $(YASMFLAGS) -I $(<D)/ -M -o $@ $< > $(@:.o=.d)
 	$(YASM) $(YASMFLAGS) -I $(<D)/ -o $@ $<
-	-@ $(if $(STRIP), $(STRIP) -wN '..@*' $@)
+	-$(STRIP) -wN '..@*' $@
 
 LIBOBJS := $(OBJS) $(SUBDIR)%.h.o $(TESTOBJS)
 $(LIBOBJS) $(LIBOBJS:.o=.i):   CPPFLAGS += -DHAVE_AV_CONFIG_H