spinlock: Disable copy, enable move, and legitimize default ctor
spinlock: Disable copy, enable move, and legitimize default ctor

This makes it easy to perform late initialization of spinlocks without
initlock.

bowlofstew/sv6,bowlofstew/sv6,bowlofstew/sv6,aclements/sv6,bowlofstew/sv6,aclements/sv6,aclements/sv6,bowlofstew/sv6,aclements/sv6,aclements/sv6