drivers: thermal: tsens: Use consistent names for variables

tsens_get_temp() uses the name 'data' for the void pointer, use the same
in tsens_get_trend() for consistency.

Remove a stray space while we're at it.

Signed-off-by: Amit Kucheria <amit.kucheria@linaro.org>
Signed-off-by: Eduardo Valentin <edubezval@gmail.com>