Copy over powerpc syscall.tbl to grab changes from the below commits

  fddb5d43 ("open: introduce openat2(2) syscall")
  9a2cef09 ("arch: wire up pidfd_getfd syscall")

Now 'perf trace' on powerpc will be able to map from those syscall
strings to the right syscall numbers, i.e.

  perf trace -e pidfd*

Will include 'pidfd_getfd' as well as:

  perf trace open*

Will cover all 'open' variants.
Reported-by: Stephen Rothwell <sfr@canb.auug.org.au>
Reviewed-by: Ravi Bangoria <ravi.bangoria@linux.ibm.com>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Aleksa Sarai <cyphar@cyphar.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Christian Brauner <christian.brauner@ubuntu.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com>
Cc: Nicholas Piggin <npiggin@gmail.com>
Cc: Sargun Dhillon <sargun@sargun.me>
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>