This increases the maximum for MVT::LAST_VALUETYPE

This increases the maximum for MVT::LAST_VALUETYPE

This change doubles the allowable value for MVT::LAST_VALUETYPE. It does
this by doing several things.

1. Introduces MVT::MAX_ALLOWED_LAST_VALUETYPE which in this change has a
value of 64.  This value contains the current maximum for the
MVT::LAST_VALUETYPE.

2. Instead of checking "MVT::LAST_VALUETYPE <= 32", all of those uses
now become "MVT::LAST_VALUETYPE <= MVT::MAX_ALLOWED_LAST_VALUETYPE"

3. Changes the dimension of the ValueTypeActions from 2 elements to four
elements and adds comments ahead of the declaration indicating the it is
"(MVT::MAX_ALLOWED_LAST_VALUETYPE/32) * 2".  This at least lets us find
what is affected if and when MVT::MAX_ALLOWED_LAST_VALUETYPE gets
changed.

4. Adds initializers for the new elements of ValueTypeActions.

This does NOT add any types in MVT. That would be done separately.

This doubles the size of ValueTypeActions from 64 bits to 128 bits and
gives us the freedom to add more types for AVX.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@74110 91177308-0d34-0410-b5e6-96231b3b80d8