MFC r365284:

MFC r365284:

Always report ENOSYS in init

While rare, encountering an unimplemented system call early in init is
catastrophic and difficult to debug.  Even after a SIGSYS handler is
registered, such configurations are problematic.  As such, always report
such events for pid 1 (following kern.lognosys if non-zero).

Reviewed by:	kevans, imp
Obtained from:	CheriBSD (plus suggestions from kevans)
Sponsored by:	DARPA
Differential Revision:	https://reviews.freebsd.org/D26288