usb: typec: Document priority and mode_selection fields in struct typec_altmode

usb: typec: Document priority and mode_selection fields in struct typec_altmode

The fields 'priority' and 'mode_selection' in struct typec_altmode are
missing from the kernel-doc comment, which results in warnings when
building the documentation with 'make htmldocs'.

WARNING: ./include/linux/usb/typec_altmode.h:44 struct member 'priority' not described in 'typec_altmode'
WARNING: ./include/linux/usb/typec_altmode.h:44 struct member 'mode_selection' not described in 'typec_altmode'

Document both fields to keep the kernel-doc comment aligned with the
structure definition.

Signed-off-by: Aldo Conte <aldocontelk@gmail.com>
Reviewed-by: Heikki Krogerus <heikki.krogerus@linux.intel.com>
Link: https://patch.msgid.link/20260311163320.61534-1-aldocontelk@gmail.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>