osmo-bts-virtual: do not print redundant info in tx_to_virt_um()
osmo-bts-virtual: do not print redundant info in tx_to_virt_um()

LOGL1S() already prints enough context information.

Change-Id: I29adf9360b96544b7f58766d5cd26d97117884d9

osmocom/osmo-bts,osmocom/osmo-bts,osmocom/osmo-bts