Moving the bcm2835 thermal driver to the broadcom directory prevented it
from getting enabled for arm64 builds, since the broadcom directory is only
available when 32-bit specific ARCH_BCM is set.

Fix this by enabling the Broadcom menu for ARCH_BCM or ARCH_BCM2835.

Fixes: 6892cf07 ("thermal: bcm2835: move to the broadcom subdirectory")
Reviewed-by: NEric Anholt <eric@anholt.net>
Signed-off-by: NAllen Wild <allenwild93@gmail.com>
Signed-off-by: NStefan Wahren <stefan.wahren@i2se.com>
Signed-off-by: NEduardo Valentin <edubezval@gmail.com>