fix flash bank auto_probe() fail with multiple targets

fix flash bank auto_probe() fail with multiple targets

  get_flash_bank_by_addr() iterates through all flash banks
trying to auto_probe() every bank, even if bank can belongs to
target other than requested, and this other target can be
in non-halted state, which leads to error message and
operation abort.
  Same situation in gdb_new_connection() and gdb_memory_map():
get_flash_bank_by_num() tries to auto_probe() requested bank,
so first get bank by get_flash_bank_by_num_noprobe(), check
if it belongs to current connection's target and skip
get_flash_bank_by_num() (actually autoprobing) if not.

Change-Id: I48b3f93dddcd9283394f14ad2de3248397c75ab3
Signed-off-by: Sergey A. Borshch <sb-sf@users.sourceforge.net>
Reviewed-on: http://openocd.zylin.com/1813
Tested-by: jenkins
Reviewed-by: Spencer Oliver <spen@spen-soft.co.uk>
Reviewed-by: Andreas Fritiofson <andreas.fritiofson@gmail.com>