staging: tidspbridge: fix error return code in omap34_xx_bridge_probe()

Fix to return a negative error code in the class_create() error
handling case instead of 0, as done elsewhere in this function.

Signed-off-by: Wei Yongjun <yongjun_wei@trendmicro.com.cn>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>