usb: typec: ucsi: Common function for the GET_PD_MESSAGE command

So far that command was only used to read the response to
the Discover Identity Request, but it is handled with two
separate functions, which is not really necessary. Squashing
the command execution into a single function. That function
can now also be used to read other messages on top of the
Request Identity response.

Signed-off-by: Heikki Krogerus <heikki.krogerus@linux.intel.com>
Link: https://lore.kernel.org/r/20240816135859.3499351-5-heikki.krogerus@linux.intel.com


Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>