Change ARM data layout strings to match llvm-gcc.

Change ARM data layout strings to match llvm-gcc.
Sandeep Patel noticed that the alignment was wrong for Neon vector types,
and this change is partly derived from his patch.  For the APCS ABI, however,
additional changes were required: the maximum ABI alignment is 32 bits and
the preferred alignment for i64 and f64 types should be 64 bits.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@128825 91177308-0d34-0410-b5e6-96231b3b80d8