[X86] Remove unneeded EVT variable. NFC

[X86] Remove unneeded EVT variable. NFC

Immediately after it is created we check if its equal to another EVT. Then we inconsistently use one or the other variables in the code below.

Instead do the equality check directly on the getValueType result and remove the variable. Use the origina VT variable throughout the remaining code.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@321406 91177308-0d34-0410-b5e6-96231b3b80d8