KVM: x86: Move Intel Processor Trace interrupt handler to vmx.c

Now that all state needed for VMX's PT interrupt handler is exposed to
vmx.c (specifically the currently running vCPU), move the handler into
vmx.c where it belongs.

Signed-off-by: Sean Christopherson <seanjc@google.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lore.kernel.org/r/20211111020738.2512932-14-seanjc@google.com