staging: ft1000: Fix goto error logic.

Fix goto error logic which could lead to kernel panics
because kthread_stop() is called in not correct error
conditions. Seen it sometimes when dsp_reload() fails
then I got kernel panic.

Signed-off-by: Marek Belisko <marek.belisko@open-nandra.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>