scripts: west: Update pyocd runner to use unified tool subcommands

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 the pyocd runner to use the new unified pyocd tool
with subcommands.

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