x86: NFC: Make getCallPreservedMask() more similar to getCalleeSavedRegs()

Changing order of checks in getCallPreservedMask() to match
getCalleeSavedRegs() so that the logic is easier to compare.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@203939 91177308-0d34-0410-b5e6-96231b3b80d8