ssb: Make bus registration failure not be silent

In kernel Bugzilla #15825, a case where routine ssb_bus_pcibus_register()
fails silently is reported. The cause for the failure is still being
investigated; however, the diagnosis would be easier if the failure
had been reported.

Signed-off-by: Larry Finger <Larry.Finger@lwfinger.net>
Signed-off-by: John W. Linville <linville@tuxdriver.com>