doc-rst: fixed kernel-doc directives in usb/typec.rst

Even if this file is not yet included in any toctree, it is parsed by
Sphinx since it is named '.rst'. This patch fixes the following two
ERRORs from Sphinx build:

Documentation/usb/typec.rst:116: ERROR: Error in "kernel-doc" directive:
invalid option block.

.. kernel-doc:: drivers/usb/typec/typec.c
   :functions: typec_register_cable typec_unregister_cable typec_register_plug
   typec_unregister_plug

Documentation/usb/typec.rst:139: ERROR: Error in "kernel-doc" directive:
invalid option block.

.. kernel-doc:: drivers/usb/typec/typec.c
   :functions: typec_set_data_role typec_set_pwr_role typec_set_vconn_role
   typec_set_pwr_opmode

Signed-off-by: Markus Heiser <markus.heiser@darmarit.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>