linux-user: Extract load_elf_image from load_elf_interp.

linux-user: Extract load_elf_image from load_elf_interp.

Moving toward a single copy of the elf binary loading code.
Fill in the details of the loaded image into a struct image_info.

Adjust create_elf_tables to read from such structures instead
of from a collection of passed arguments.  Don't return error
values from load_elf_interp; always exit(-1) with a message to
stderr.  Collect elf_interpreter handling in load_elf_binary
to a common spot.

Signed-off-by: Richard Henderson <rth@twiddle.net>
Signed-off-by: Edgar E. Iglesias <edgar.iglesias@gmail.com>