Fix warning "not checking return value of fscanf" in lib/utils.c: get_psched_settings

Fix warning "not checking return value of fscanf" in lib/utils.c: get_psched_settings

Also, change internal variables type from uint32_t to unsigned int.
Correct scanf format string should contain "SCNx32" instead of just "x",
but I decide not to fix that and just changed variable type.