Provide a crutch that prevents watchdog to interrupt dumping
on a box with IPMI enabled.

Okay from:	jhb
Sponsored by:	Netflix
Sponsored by:	Nginx, Inc.
Rename the VMM_CTRx() family of macros to VCPU_CTRx() to highlight that these
tracepoints are vcpu-specific.

Add support for tracepoints that are global to the virtual machine - these
tracepoints are called VM_CTRx().