An instance of the NAX apploader already has an existing NAX instance in
memory. Calling directly into IdentifyType() directly would re-parse the
whole file again into yet another NAX instance, only to toss it away
again.
This gets rid of unnecessary/redundant file parsing and allocations.
AsNCA() allocates an NCA instance every time it's called. In the current
manner it's used, it's quite inefficient as it's making a redundant
allocation.
We can just amend the order of the conditionals to make it easier to
just call it once.