[RFA] Make dwarf2_free_objfile static

[Simon Marchi]

On 2018-06-27 18:31, Andrew Burgess wrote:
> I don't know if we have a preference for static_cast over C style
> casting these days?

Indeed, static_cast provides some compile-time safety, so I guess we 
should always prefer that over the C-style cast.

> Otherwise, FWIW, this looks like a nice clean up.

Indeed, LGTM (with possibly the cast fixed up).

Thanks,

Simon