thermal: ti-soc-thermal: Fix reversed condition in ti_thermal_expose_sensor()

[ Upstream commit 0f348db01fdf128813fdd659fcc339038fb421a4 ]

This condition is reversed and will cause breakage.

Fixes: 7440f518dad9 ("thermal/drivers/ti-soc-thermal: Avoid dereferencing ERR_PTR")
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Link: https://lore.kernel.org/r/20200616091949.GA11940@mwanda


Signed-off-by: Sasha Levin <sashal@kernel.org>