More sanitizing for wrong bDefaultFrameIndex values.  Fixes a panic at attach time for devices which set bDefaultFrameIndex larger than the existing frame descriptors.
More sanitizing for wrong bDefaultFrameIndex values.  Fixes a panic
at attach time for devices which set bDefaultFrameIndex larger than
the existing frame descriptors.

Spotted, tested, and OK yuo@

orumin/openbsd-efivars,orumin/openbsd-efivars,orumin/openbsd-efivars,orumin/openbsd-efivars