gdb/dwarf: remove unnecessary parameter of create_cus_hash_table

We can use `cu->per_objfile` instead of passing down a
dwarf2_per_objfile explicitly.

Change-Id: Ie1fd93d9e7a74d09b857f1f0909d7441b79ed893
Approved-By: Tom Tromey <tom@tromey.com>
1 file changed