Use size_t in gdb_bfd_section_data

BFD recently changed bfd_mmap to use size_t, not bfd_size_type.  This
patch updates gdb_bfd_section_data to follow.  Without this patch, if
the two types ever differ, gdb would fail to build.

Approved-By: Simon Marchi <simon.marchi@efficios.com>
1 file changed