tools/latency-collector: Check pkg-config install

The tool pkg-config used to check libtraceevent and libtracefs, if not
installed, it will report the libs not found, even though they have
already been installed.

Before:
libtraceevent is missing. Please install libtraceevent-dev/libtraceevent-devel
libtracefs is missing. Please install libtracefs-dev/libtracefs-devel

After:
Makefile.config:10: *** Error: pkg-config needed by libtraceevent/libtracefs is missing
on this system, please install it.

Link: https://lore.kernel.org/[e-mail]
Fixes: 9d56c88e5225 ("tools/tracing: Use tools/build makefiles on latency-collector")
Signed-off-by: Tao Chen <[e-mail]>
Signed-off-by: Steven Rostedt (Google) <[e-mail]>

tools/tracing/latency/Makefile.config

···
 # SPDX-License-Identifier: GPL-2.0-only
 
+include $(srctree)/tools/scripts/utilities.mak
+
 STOP_ERROR :=
+
+ifndef ($(NO_LIBTRACEEVENT),1)
+  ifeq ($(call get-executable,$(PKG_CONFIG)),)
+    $(error Error: $(PKG_CONFIG) needed by libtraceevent/libtracefs is missing on this system, please install it)
+  endif
+endif
 
 define lib_setup
   $(eval LIB_INCLUDES += $(shell sh -c "$(PKG_CONFIG) --cflags lib$(1)"))