[DWARFCallFrameInfo] Add Type enum to differentiate eh/debug_frame sections

Summary:
instead of using a boolean to differentiate between the two section
types, use an enum to make the intent clearer.

I also remove the RegisterKind argument from the constructor, as this
can be deduced from the Type argument.

Reviewers: clayborg, jasonmolenda

Subscribers: lldb-commits

Differential Revision: https://reviews.llvm.org/D34681

llvm-svn: 306521