ethernet: ucc_geth: inform the compiler that numQueues is always 1

The numQueuesTx and numQueuesRx members of struct ucc_geth_info are
never set to anything but 1, and never have been. It's unclear how
well the code supporting multiple queues would work. Until somebody
wants to play with enabling that, help the compiler eliminate a lot of
dead code and loops that are not really loops by creating static
inline helpers. If and when the numQueuesTx/numQueuesRx fields are
re-introduced, it suffices to update those helper to return the
appropriate field.

This cuts the .text segment of ucc_geth.o by 8%.

Signed-off-by: Rasmus Villemoes <rasmus.villemoes@prevas.dk>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>