FamStructWrapper: validate maximum capacity when doing new #99
Description
The new function in FamStructWrapper is not validating that num_elements is less than the maximum capacity that the type supports (as defined in FamStruct::max_len), and thus might result in allocating more elements than it was initially intended.
A change in FamStructWrapper requires changes in kvm-bindings as well, so we might want to fix the vmm-sys-util dependency in kvm-bindings before doing a release. It might be better to remove the vmm-sys-util dependency from kvm-bindings (as this change does not pertain to the scope of kvm-bindings), and implement FamStruct directly in kvm-ioctls where it is actually needed.