fixes typo port_managment_error -> port_management_error

Signed-off-by: Geoff Salmon <gsalmon@se-instruments.com>
factors out functions for sending mgmt errors from clock and port

Adds port_management_send_error and clock_management_send_error to
avoid repeatedly checking the result of port_managment_send_error and
calling pr_err if it failed. Future patches send more mgmt errors so
this will avoid repeated code.

Signed-off-by: Geoff Salmon <gsalmon@se-instruments.com>
send UNKNOWN_ID error for unknown management TLVs

Signed-off-by: Geoff Salmon <gsalmon@se-instruments.com>
adds stub clock/port_management_set functions

Signed-off-by: Geoff Salmon <gsalmon@se-instruments.com>
send NOT_SUPPORTED errors for all unhandled, known management IDs

Now that there are clock/port_management_set functions, the IDs that
GETs are handled for, like DEFUALT_DATA_SET, still need to be in the
case for sending NOT_SUPPORTED errors.

Signed-off-by: Geoff Salmon <gsalmon@se-instruments.com>
send errors if mgmt tlv length doesn't match action

It's especially important to check that SET messages aren't empty.

Signed-off-by: Geoff Salmon <gsalmon@se-instruments.com>