Allow the vfs.nfsd knobs to be set from loader.conf (or using
kenv(8)).  This is useful when nfsd is loaded as module.

Reviewed by:	rmacklem
Sponsored by:	The FreeBSD Foundation
MFC after:	1 week
Add a method to iicbus to request IIC_M_NOSTOP behaviour for multibyte
transfers to be default.  It simplifies porting code which assumes
such settings.

Discussed with:	avg, llos, nwhitehorn
Sponsored by:	The FreeBSD Foundation
MFC after:	1 week