vmm(4)/vmd(8): include pending interrupt in vm_run_parmams.

vmm(4)/vmd(8): include pending interrupt in vm_run_parmams.

To remove an ioctl(2) from the vcpu thread hotpath in vmd(8), add
a flag in the vm_run_params structure to indicate if there's another
interrupt pending. This reduces latency in vcpu work related to
i/o as we save a trip into the kernel just to flip the interrupt
pending flag on or off.

Tested by phessler@, mbuhl@, stsp@, and Mischa Peters.

ok mlarkin@