arm64: defconfig: Re-enable bcm2835-thermal driver

The bcm2835-thermal driver was added with commit ac178e42
("ARM64: bcm2835: add thermal driver to default config"). Unfortunately
this was accidentally dropped by commit eb1e6716
("arm64: defconfig: sync with savedefconfig"). So enable the driver again.

Fixes: eb1e6716

 ("arm64: defconfig: sync with savedefconfig")
Signed-off-by: Stefan Wahren <stefan.wahren@i2se.com>
Signed-off-by: Olof Johansson <olof@lixom.net>