perf build: Make minimal shellcheck version to v0.6.0

The perf build failed due to the shellcheck on my machine (v0.4.6 on Ubuntu
18.04.1 LTS) doesn't support -a/--check-sourced and -S/--severity option.

These two options are introduced in shellcheck v0.4.7 and v0.6.0
respectively. So restrict the minimal version of shellcheck to v0.6.0.

Fixes: b809fc656e763296 ("perf build: Shellcheck support for OUTPUT directory")
Reviewed-by: Ian Rogers <[e-mail]>
Signed-off-by: Yicong Yang <[e-mail]>
Cc: Alexander Shishkin <[e-mail]>
Cc: Jiri Olsa <[e-mail]>
Cc: Junhao He <[e-mail]>
Cc: Mark Rutland <[e-mail]>
Cc: Namhyung Kim <[e-mail]>
Cc: Peter Zijlstra <[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

···
   SHELLCHECK := $(shell which shellcheck 2> /dev/null)
 endif
 
+# shellcheck is using in tools/perf/tests/Build with option -a/--check-sourced (
+# introduced in v0.4.7) and -S/--severity (introduced in v0.6.0). So make the
+# minimal shellcheck version as v0.6.0.
+ifneq ($(SHELLCHECK),)
+  ifeq ($(shell expr $(shell $(SHELLCHECK) --version | grep version: | \
+        sed -e 's/.\+ \([0-9]\+\).\([0-9]\+\).\([0-9]\+\)/\1\2\3/g') \< 060), 1)
+    SHELLCHECK :=
+  endif
+endif
+
 export srctree OUTPUT RM CC CXX LD AR CFLAGS CXXFLAGS V BISON FLEX AWK
 export HOSTCC HOSTLD HOSTAR HOSTCFLAGS SHELLCHECK