perf symbols: Fixup vsyscall maps

perf symbols: Fixup vsyscall maps

While debugging a problem reported by Pekka Enberg by printing
the IP and all the maps for a thread when we don't find a map
for an IP I noticed that dso__load_sym needs to fixup these
extra maps it creates to hold symbols in different ELF sections
than the main kernel one.

Now we're back showing things like:

[root@doppio linux-2.6-tip]# perf report | grep vsyscall
     0.02%             mutt  [kernel.kallsyms].vsyscall_fn  [.] vread_hpet
     0.01%            named  [kernel.kallsyms].vsyscall_fn  [.] vread_hpet
     0.01%   NetworkManager  [kernel.kallsyms].vsyscall_fn  [.] vread_hpet
     0.01%         gconfd-2  [kernel.kallsyms].vsyscall_0   [.] vgettimeofday
     0.01%  hald-addon-rfki  [kernel.kallsyms].vsyscall_fn  [.] vread_hpet
     0.00%      dbus-daemon  [kernel.kallsyms].vsyscall_fn  [.] vread_hpet
[root@doppio linux-2.6-tip]#

Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Frédéric Weisbecker <fweisbec@gmail.com>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Pekka Enberg <penberg@cs.helsinki.fi>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Paul Mackerras <paulus@samba.org>
LKML-Reference: <1265223128-11786-2-git-send-email-acme@infradead.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>