thermal/drivers/bcm2711: Don't clamp temperature at zero

thermal/drivers/bcm2711: Don't clamp temperature at zero

[ Upstream commit 106e0121e243de4da7d634338089a68a8da2abe9 ]

The thermal sensor on BCM2711 is capable of negative temperatures, so don't
clamp the measurements at zero. Since this was the only use for variable t,
drop it.

This change based on a patch by Dom Cobley, who also tested the fix.

Fixes: 59b781352dc4 ("thermal: Add BCM2711 thermal driver")
Signed-off-by: Stefan Wahren <stefan.wahren@i2se.com>
Acked-by: Florian Fainelli <f.fainelli@gmail.com>
Link: https://lore.kernel.org/r/20220412195423.104511-1-stefan.wahren@i2se.com
Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>