thermal: Remove ARCH_KIRKWOOD dependency

thermal: Remove ARCH_KIRKWOOD dependency

mach-kirkwood has been removed, now that kirkwood lives in mach-mvebu.
Depend on MACH_KIRKWOOD, which will be set when kirkwood is built as
part of ARCH_MVEBU.

Signed-off-by: Andrew Lunn <andrew@lunn.ch>
Cc: Zhang Rui <rui.zhang@intel.com>
Cc: linux-pm@vger.kernel.org
Acked-by: Eduardo Valentin <edubezval@gmail.com>
Link: https://lkml.kernel.org/r/1409417172-6846-4-git-send-email-andrew@lunn.ch
Signed-off-by: Jason Cooper <jason@lakedaemon.net>