The function atomic_set return the previous value of the
target. Sometimes this value is irrelevant, e.g when initializing a
variable.
As MISRA-C rule 17.7 requires that the value returned by a non-void
function must be used, we have to explicitly ignore some cases.
MISRA-C rule 17.7
Signed-off-by: Flavio Ceolin <flavio.ceolin@intel.com>