libutil: Fix a bunch of manual page issues.
kernel/i915: Add missing prototype.
kernel/drm: Fix some warnings due to our vm_paddr_t being 64 bits on i386.
x86_64: Add machdep.cpu.mwait.bm_sts to bypass BM_STS check

Default still applies BM_STS check.  Useful for some broken BIOS.