Its not just an rb_node, it carries extra state that is private to the
browser. And will carry some more in the next patches.

Better name it browser_disasm_line, i.e. something derived from
disasm_line, that specializes it.

Cc: David Ahern <dsahern@gmail.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Namhyung Kim <namhyung@gmail.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Link: http://lkml.kernel.org/n/tip-nev4b97vdvv35we1qmooym52@git.kernel.orgSigned-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>