Relax type checking for a few Neon intrinsics. <rdar://problem/10538555>

Not long ago, I tightened up the type checking for pointer arguments of
Neon intrinsics to match the specifications provided by ARM.  One consequence
was that it became impossible to access the unaligned versions of a few
Neon load/store operations.  Since there are just a few of these intrinsics
where it makes a difference, I think it's better to relax the type checking
than to either introduce new non-standard unaligned intrinsics or to disallow
intrinsics for the unaligned operations.

llvm-svn: 146963