wireless: b43: fix error path in SDIO

Fix unbalanced call to sdio_release_host() on the error path.

Signed-off-by: Guennadi Liakhovetski <g.liakhovetski@gmx.de>
Acked-by: Larry Finger <Larry.Finger@lwfinger.net>
Cc: stable@kernel.org
Signed-off-by: John W. Linville <linville@tuxdriver.com>