MFC: r219036

MFC: r219036

Silence 'out of chain frames' warnings and bump the number of frames.

mps.c:		Hide the 'out of chain frames' warning behind MPS_INFO.

mps_sas.c:	Hide the SIM queue freeze/unfreeze messages behind MPS_INFO.

mpsvar.h:	Bump the number of chain frames from 1024 to 2048.  From
		testing, it looks like this makes it less likely that we'll
		run out of chain frames, and it doesn't cost much memory
		(32K).

git-svn-id: svn://svn.freebsd.org/base/stable/8@219099 ccf9f872-aa2e-dd11-9fc8-001c23d0bc1f