coredump/elf: Pass coredump_params into fill_note_info

Instead of individually passing cprm->siginfo and cprm->regs
into fill_note_info pass all of struct coredump_params.

This is preparation to allow fill_files_note to use the existing
vma snapshot.

Reviewed-by: Jann Horn <jannh@google.com>
Reviewed-by: Kees Cook <keescook@chromium.org>
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>