MFC r300011

MFC r300011

sfxge(4): only raise an exception after MC assert or reboot in the common code

Fix efx_mcdi_request_poll so it only raises an exception if EIO is
reported from a detected MC assert or reboot. This prevents
an unnecessary exception being raised if an MCDI response error code
is trandlated to EIO.

Submitted by:   Andy Moreton <amoreton at solarflare.com>
Sponsored by:   Solarflare Communications, Inc.

git-svn-id: svn://svn.freebsd.org/base/stable/10@301383 ccf9f872-aa2e-dd11-9fc8-001c23d0bc1f