[llvm][NFC] Use CallBase instead of Instruction in ProfileSummaryInfo

Summary:
getProfileCount requires the parameter be a valid CallBase, and its uses
reflect that.

Reviewers: dblaikie, craig.topper, wmi

Subscribers: eraman, hiraditya, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D78940