misc: ti-st: Fix memory leak in the error path of probe()

Free resources instead of direct return of the error code if kim_probe
fails.

Found by Linux Driver Verification project (linuxtesting.org).

Signed-off-by: Anton Vasilyev <vasilyev@ispras.ru>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>