perf tools: Add includes for detected configs in Makefile.perf

Makefile.perf uses "CONFIG_*" checks in the code. Example the config for
libtraceevent is used to set PYTHON_EXT_SRCS

ifeq ($(CONFIG_LIBTRACEEVENT),y)
PYTHON_EXT_SRCS := $(shell grep -v ^\# util/python-ext-sources)
else
PYTHON_EXT_SRCS := $(shell grep -v '^\#\|util/trace-event.c' util/python-ext-sources)
endif

But this is not picking the value for CONFIG_LIBTRACEEVENT that is set
using the settings in Makefile.config. Include the file
".config-detected" so that make will use the system detected
configuration in the CONFIG checks.

This will fix isues that could arise when other "CONFIG_*" checks are
added to Makefile.perf in future as well.

Reviewed-by: Ian Rogers <[e-mail]>
Signed-off-by: Athira Rajeev <[e-mail]>
Cc: Disha Goel <[e-mail]>
Cc: Jiri Olsa <[e-mail]>
Cc: Kajol Jain <[e-mail]>
Cc: Madhavan Srinivasan <[e-mail]>
Cc: Namhyung Kim <[e-mail]>
Cc: [e-mail]
Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: Arnaldo Carvalho de Melo <[e-mail]>

tools/perf/Makefile.perf

···
 
 python-clean := $(call QUIET_CLEAN, python) $(RM) -r $(PYTHON_EXTBUILD) $(OUTPUT)python/perf*.so
 
+# Use the detected configuration
+-include $(OUTPUT).config-detected
+
 ifeq ($(CONFIG_LIBTRACEEVENT),y)
   PYTHON_EXT_SRCS := $(shell grep -v ^\# util/python-ext-sources)
 else