cpuidle: kirkwood: Remove ARCH_KIRKWOOD dependency

mach-kirkwood has been removed, now that kirkwood lives in mach-mvebu.
Use MACH_KIRKWOOD, which is set when kirkwood is built as part of
mach-mvebu.
Signed-off-by: NAndrew Lunn <andrew@lunn.ch>
Cc: Daniel Lezcano <daniel.lezcano@linaro.org>
Cc: Rafael J. Wysocki <rjw@rjwysocki.net>
Cc: linux-pm@vger.kernel.org
Acked-by: NDaniel Lezcano <daniel.lezcano@linaro.org>
Acked-by: NRafael J. Wysocki <rjw@rjwysocki.net>
Link: https://lkml.kernel.org/r/1409417172-6846-2-git-send-email-andrew@lunn.chSigned-off-by: NJason Cooper <jason@lakedaemon.net>

drivers/cpuidle/Kconfig.arm

@@ -28,7 +28,7 @@ config ARM_HIGHBANK_CPUIDLE
 
 config ARM_KIRKWOOD_CPUIDLE
 	bool "CPU Idle Driver for Marvell Kirkwood SoCs"
-	depends on ARCH_KIRKWOOD || MACH_KIRKWOOD
+	depends on MACH_KIRKWOOD
 	help
 	  This adds the CPU Idle driver for Marvell Kirkwood SoCs.