[AArch64] remove bogus comment; NFC

I added this comment with D42323, but as discussed in D42806, the architecture
does the right thing for denorms. We don't even need the select on 0.0 here?


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@323996 91177308-0d34-0410-b5e6-96231b3b80d8
1 file changed