Rename the M68kOperand::Type enumeration to KindTy to avoid ambiguity
with the Kind field when referencing enumeration values e.g.
`Kind::Value`.

This works around a compilation error under GCC 5, where GCC won't
lookup enum class values if you have a similarly named field
(see https://gcc.gnu.org/bugzilla/show_bug.cgi?id=60994).

The error in question is:
`M68kAsmParser.cpp:857:8: error: 'Kind' is not a class, namespace, or enumeration`

Differential Revision: https://reviews.llvm.org/D108723

* [InstCombine] Add tests for "eq of parts" with logical op (NFC)

We currently only handle this with a bitwise and/or instruction,
but not a logical.

(cherry picked from commit be4b836)

* [InstCombine] Perform "eq of parts" fold with logical ops

The pattern matched here is too complex for the general logical
and/or to bitwise and/or conversion to trigger. However, the
fold is poison-safe, so match it with a select root as well:

https://alive2.llvm.org/ce/z/vNzzSg
https://alive2.llvm.org/ce/z/Beyumt
(cherry picked from commit fafe5a6)

Fixes PR51626.

The M68k requires that all instruction, word and long word reads are
aligned to word boundaries. From the 68020 onwards, there is a
performance benefit from aligning long words to long word boundaries.

The M68k uses the same data layout for pointers and integers.

In line with this, this commit updates the pointer data layout to
match the layout already set for 32-bit integers: 32:16:32.

Differential Revision: https://reviews.llvm.org/D108792