cvs commit: src/sys/dev/mxge if_mxge.c

[Andrew Gallatin]

Scott Long writes:
 > Yeah, I can't stress enough that busdma maps are opaque handles and
 > should always be handled like they are valid.  It's only an
 > implementation detail that they are often NULL on i386 and amd64.

It was overly cautious resource freeing code, influenced by lots
of programming on other OSes, where free(NULL) is a panic :(
I was able to simplify it some..

FWIW, I've got one small leak of 2 "temp" items left that I'm going to
wait for dtrace to track down.

Drew