tifm_sd: treat "status error" as normal command completion

TI FlasMedia controller attempts to validate command responses and
issues a "status error" if response does not matches its perceived
(by controller) value. As mmc layer does its own validation we can
safely ignore the controller's opinion.

Signed-off-by: Alex Dubov <oakad@yahoo.com>
Signed-off-by: Pierre Ossman <drzeus@drzeus.cx>