bhyvectl: Address compiler warnings and bump WARNS

[markj]

Summary

Avoid unaligned accesses in cpu_vendor_intel() and address a few other
nits. No functional change intended.

[jhb]

usr.sbin/bhyvectl/bhyvectl.c

657

I think more correct would be to do something along the lines of:

u_int v[3];

...
v[0] = regs[1];
v[1] = regs[3];
v[2] = regs[2];

if (memcmp(v, "GenuineIntel", sizeof(v)) == 0)

etc. It is always a 12 byte comparison and doesn't vary based on the vendor string length. Instead, vendors always adopt a 12 byte string as their signature.

[corvink]

I'd prefer Johns approach.

[markj]

Apply jhb's suggestion.