package/tpm2-totp: fix error due to variable used uninitialized

Some inline declarations of strtok_r (specifically in Sourcery CodeBench
Lite 2016.11-19) contain code where an '__s' local variable can be used
uninitialized.

When GCC expands that declaration in tpm2-totp, __s becomes an alias to
a variable which fact is not initialized, but this is not relevant since
the execution path leading to the uninitialized use is never followed.

Anyway, apply a patch already submitted upstream to fix the compilation
error.

Upstream bug report:
  https://github.com/tpm2-software/tpm2-totp/issues/32

Fixes:
  http://autobuild.buildroot.net/results/5693a35e4d6bc76a1f46fe0e217abc49f7188aad/



Signed-off-by: Carlos Santos <unixmania@gmail.com>
Signed-off-by: Peter Korsgaard <peter@korsgaard.com>