gbsim/loopback_test: remove unused variables
gbsim/loopback_test: remove unused variables

Two dangling unused variables caught by compiling -Wall.

Signed-off-by: Bryan O'Donoghue <165dc05575478af93ac2f97f67be6e1756010094@linaro.org>
Reported-by: Greg Kroah-Hartman <4645f7897fd33786a2ee1264d590b3c400559d85@google.com>
Signed-off-by: Greg Kroah-Hartman <4645f7897fd33786a2ee1264d590b3c400559d85@google.com>

projectara/gbsim,projectara/gbsim,gregkh/gbsim,gregkh/gbsim