perf bpf: Do not use llvm-strip on BPF binary

llvm-strip is not really required. Remove this dependency to make it
easier to build perf with BUILD_BPF_SKEL=1.

Committer notes:

This removes the need for the 'llvm' package just to get llvm-strip.
Reported-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Signed-off-by: Song Liu <song@kernel.org>
Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Ian Rogers <irogers@google.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

tools/perf/Makefile.perf

@@ -181,7 +181,6 @@ HOSTCC  ?= gcc
 HOSTLD  ?= ld
 HOSTAR  ?= ar
 CLANG   ?= clang
-LLVM_STRIP ?= llvm-strip
 
 PKG_CONFIG = $(CROSS_COMPILE)pkg-config
 
@@ -1083,7 +1082,7 @@ $(BPFTOOL): | $(SKEL_TMP_OUT)
 
 $(SKEL_TMP_OUT)/%.bpf.o: util/bpf_skel/%.bpf.c $(LIBBPF) | $(SKEL_TMP_OUT)
 	$(QUIET_CLANG)$(CLANG) -g -O2 -target bpf -Wall -Werror $(BPF_INCLUDE) $(TOOLS_UAPI_INCLUDE) \
-	  -c $(filter util/bpf_skel/%.bpf.c,$^) -o $@ && $(LLVM_STRIP) -g $@
+	  -c $(filter util/bpf_skel/%.bpf.c,$^) -o $@
 
 $(SKEL_OUT)/%.skel.h: $(SKEL_TMP_OUT)/%.bpf.o | $(BPFTOOL)
 	$(QUIET_GENSKEL)$(BPFTOOL) gen skeleton $< > $@