cavium/liquidio: Remove unused lio_get_device_id

lio_get_device_id() has been unused since 2018's
commit 64fecd3e ("liquidio: remove obsolete functions and data
structures")

Remove it.

Signed-off-by: Dr. David Alan Gilbert <linux@treblig.org>
Reviewed-by: Simon Horman <horms@kernel.org>
Link: https://patch.msgid.link/20250203183343.193691-1-linux@treblig.org


Signed-off-by: Jakub Kicinski <kuba@kernel.org>