perf trace: Add beautifier script for fsmount flags

perf trace: Add beautifier script for fsmount flags

And move the existing one to fsmount_attr.sh to be more precise.
Now the fsmount_flags[] is generated from the mount.h like below.
The ilog2() + 1 is an existing pattern to handle bit flags.

  $ cat tools/perf/trace/beauty/generated/fsmount_arrays.c
  static const char *fsmount_flags[] = {
  	[ilog2(0x00000001) + 1] = "CLOEXEC",
  	[ilog2(0x00000002) + 1] = "NAMESPACE",
  };

It was found by Sashiko during the review.

Reviewed-by: Ian Rogers <irogers@google.com>
Signed-off-by: Namhyung Kim <namhyung@kernel.org>