Inline vmresume() and vmlaunch()
Inline vmresume() and vmlaunch()

In #56's discussion I noted that "there are no strong reasons to use inline for
VMX intrinsics".

I was wrong: it's practically impossible to use `x86::bits64::vmx::vmresume()`
due to it being a function. The reason is that VMRESUME is usually called after
restoring the guest state, which includes stack pointer.

As the stack pointer now corresponds to guest address space and CALL to
`x86::bits64::vmx::vmresume()` accesses the stack, this results in triple fault
exception.

`x86::bits64::vmx::vmlaunch()` was also inlined because in practice it has
similar pitfalls, and even through they can be avoided, an inlined version of
this function is less surprising.

gz/rust-x86,gz/rust-x86