Fix build breakage caused by ixl driver

Fix missing includes and invalid vars in ixl / ixlv driver added by r270346
which caused build failures for GENERIC kernel after it was made default
by r270755.

X-MFC-With: r270346 / r270755
Sponsored by:	Multiplay


git-svn-id: svn+ssh://svn.freebsd.org/base/head@270758 ccf9f872-aa2e-dd11-9fc8-001c23d0bc1f