Prune Pass.h include from DataLayout.h. NFCI

Summary:
Reduce include dependencies by no longer including Pass.h from
DataLayout.h. That include seemed irrelevant to DataLayout, as
well as being irrelevant to several users of DataLayout.

Reviewers: rnk

Reviewed By: rnk

Subscribers: mehdi_amini, hiraditya, cfe-commits, llvm-commits

Tags: #clang, #llvm

Differential Revision: https://reviews.llvm.org/D69261

llvm-svn: 375436