net: ipa: don't reset an ALLOCATED channel

If the rmnet_ipa0 network device has not been opened at the time
we remove or shut down the IPA driver, its underlying TX and RX
GSI channels will not have been started, and they will still be
in ALLOCATED state.

The RESET command on a channel is meant to return a channel to
ALLOCATED state after it's been stopped.  But if it was never
started, its state will still be ALLOCATED, the RESET command
is not required.

Quietly skip doing the reset without printing an error message if a
channel is already in ALLOCATED state when we request it be reset.

Signed-off-by: Alex Elder <elder@linaro.org>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>