[media] v4l: ti-vpe: fix error return code in vpe_probe()

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

Signed-off-by: Wei Yongjun <yongjun_wei@trendmicro.com.cn>
Reviewed-by: Archit Taneja <archit@ti.com>
Signed-off-by: Mauro Carvalho Chehab <m.chehab@samsung.com>