perf build failure in v6.1.53-221-g5e5c3289d389

make tools/perf fails with

gcc: fatal error: no input files

Bisect points to 'perf build: Update build rule for generated files' which adds

+ +# pmu-events.c file is generated in the OUTPUT directory so it needs a +# separate rule to depend on it properly +$(OUTPUT)pmu-events/pmu-events.o: $(PMU_EVENTS_C) + $(call rule_mkdir) + $(call if_changed_dep,cc_o_c)

but there is no PMU_EVENTS_C in v6.1.y.

Guenter