perf augmented_raw_syscalls: Support copying two string syscall args

perf augmented_raw_syscalls: Support copying two string syscall args

Starting with the renameat and renameat2 syscall, that both receive as
second and fourth parameters a pathname:

  # perf trace -e rename* mv one ANOTHER
  LLVM: dumping /home/acme/git/perf/tools/perf/examples/bpf/augmented_raw_syscalls.o
  mv: cannot stat 'one': No such file or directory
  renameat2(AT_FDCWD, "one", AT_FDCWD, "ANOTHER", RENAME_NOREPLACE) = -1 ENOENT (No such file or directory)
  #

Since the per CPU scratch buffer map has space for two maximum sized
pathnames, the verifier is satisfied that there will be no overrun.

Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Luis Cláudio Gonçalves <lclaudio@redhat.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Link: https://lkml.kernel.org/n/tip-x2uboyg5kx2wqeru288209b6@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>