Delete AArch64II::MO_CONSTPOOL.

A constant pool holding the address of a variable in equivalent to
a got entry. It produces exactly the same instruction sequence as a
got use and unlike a got use this is not uniqued by the linker.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@271311 91177308-0d34-0410-b5e6-96231b3b80d8
7 files changed