TargetLoweringBase: Remove unnecessary watchos exception; NFC

WatchOS isn't report as iOS (as opposed to tvos) so the exception I
added in my last commit wasn't necessary after all.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@321041 91177308-0d34-0410-b5e6-96231b3b80d8
1 file changed