common/l1sap.c: fix: add missing new line to a debug message
common/l1sap.c: fix: add missing new line to a debug message

Change-Id: I7c0dab255289a5847d1a0af009e8962e4410e5ca

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