pyocd 0.14.0 merged its command-line tools into a unified pyocd tool
with subcommands. The separate command-line tools still remain, but are
deprecated. Update all pyocd calls in samples and documentation to use
the new unified pyocd tool with subcommands.

Note that pyocd 0.15.0 has an issue with the command 'pyocd erase',
which was fixed in pyocd 0.16.0.

Signed-off-by: Maureen Helm <maureen.helm@nxp.com>