drivers: thermal: tsens: Simplify code flow in tsens_probe

Move platform_set_drvdata up to avoid an extra 'if (ret)' check after
the call to tsens_register.

Signed-off-by: Amit Kucheria <amit.kucheria@linaro.org>
Reviewed-by: Stephen Boyd <swboyd@chromium.org>
Reviewed-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Link: https://lore.kernel.org/r/184422dcc1c12553e71a58c62e01425fd7d1172a.1572526427.git.amit.kucheria@linaro.org