module: fix missing unlock
module: fix missing unlock

When failing to get a input var, function was returning without
unlocking mdata->read_lock

Signed-off-by: Bruno Dilly <ea4fb6320c1221b6a559089d8ab97ffc53fc6586@intel.com>

solettaproject/soletta-machine-learning,anselmolsm/soletta-machine-learning,anselmolsm/soletta-machine-learning,solettaproject/soletta-machine-learning,anselmolsm/soletta-machine-learning,solettaproject/soletta-machine-learning