thermal: Rephrase the Kconfig text for thermal

thermal: Rephrase the Kconfig text for thermal

The thermal subsystem may have relied on sysfs in 2008 when it
was introduced, but these days the thermal zones will more often
than not come from the hardware descriptions and not from sysfs.

Drop the "Generic" phrases as well: there are no non-generic
drivers that I know of, the thermal framework is by definition
generic.

Reword a bit and fix some grammar.

[ Daniel Lezcano ] : fixed Randy's comment s/offers/offer/

Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Acked-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Link: https://lore.kernel.org/r/20200229204527.143796-1-linus.walleij@linaro.org