The controller does not zero this data structure, ever.

Zero it out here so we do not misinterpret the data error.

Obtained from:	Yahoo! Inc.
MFC after:	2 weeks
Silence warning from clang:

/home/sbruno/bsd/head/sys/dev/hptrr/hptrr_osm_bsd.c:178:66: warning: for loop has empty body [-Wempty-body]
                for (order=0, size=PAGE_SIZE; size<f->size; order++, size<<=1) ;
                                                                               ^
/home/sbruno/bsd/head/sys/dev/hptrr/hptrr_osm_bsd.c:178:66: note: put the semicolon on a separate line to silence this warning

Obtained from:	Yahoo! Inc.
MFC after:	2 weeks
Correct comment typo's
Add missing comment

Reviewed by:	pjd (mentor)
Approved by:	pjd (mentor)
MFC after:	2 weeks