Rename getLargestLegalIntTypeSize to getLargestLegalIntTypeSizeInBits(). NFC.

Summary: Rename DataLayout::getLargestLegalIntTypeSize to DataLayout::getLargestLegalIntTypeSizeInBits() to prevent similar mistakes  fixed in r269433.

Reviewers: joker.eph, mcrosier

Subscribers: mcrosier, llvm-commits

Differential Revision: http://reviews.llvm.org/D20248

llvm-svn: 269456