[AArch64][RegisterBankInfo] Fix typo in the logic used in assert.

Thanks to David Binderman <dcb314@hotmail.com> for bringing it to my
attention.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@288688 91177308-0d34-0410-b5e6-96231b3b80d8
1 file changed