In sys/sparc64/sparc64/spitfire.c, prevent signed shift overflow by
casting to the appropriate type.  (Note this fix cannot be done in
sys/sparc64/sparc64/spitfire.c, since that file is also included by
assembly source files.)

Reviewed by:	marius
MFC after:	3 days
Make sure a for loop in fire_alloc_msix() terminates, by making the loop
counter signed.

Reviewed by:	marius
MFC after:	3 days