map capability string for VM_CAP_BPT_EXIT

[rew]

Summary

This patch adds a descriptive string for mapping to the VM_CAP_BPT_EXIT.
I noticed this when using bhyvectl to identify the vmm capabilities.

Test Plan

without patch:

$ bhyvectl --vm vm --getcap
Capability "hlt_exit" is set on vcpu 0
Capability "mtrap_exit" is not available
Capability "pause_exit" is set on vcpu 0
Capability "unrestricted_guest" is set on vcpu 0
Capability "enable_invpcid" is not available
Capability "(null)" is not available

with patch:

$ bhyvectl --vm vm --getcap
Capability "hlt_exit" is set on vcpu 0
Capability "mtrap_exit" is not available
Capability "pause_exit" is set on vcpu 0
Capability "unrestricted_guest" is set on vcpu 0
Capability "enable_invpcid" is not available
Capability "bpt_exit" is not available

[rgrimes]

Looks like this was missed in commit rS355724 for review D20309.

[jhb]

BTW, I would suggest replacing this structure with one indexed by the enum values and using nitems() and C99 initializers as a followup change, e.g.:

static const char *capstrmap[] = {
   [VM_CAP_HALT_EXIT] = "hlt_exit",
   ...
};

const char *
vm_capability_type2name(int type)
{
    if (type < nitems(capstrmap))
        return (capstrmap[type]);
    else
        return (NULL);
}

vm_capability_name2type would still have to do a loop, but would use`'i < nitems(capstrmap)` as the terminating condition for the loop.

[rew]

Updating D24289: map capability string for VM_CAP_BPT_EXIT

John, per your suggestion.

capstrmap is now indexed by enum vm_cap_type.