ARM: cpuidle: Enable the ARM64 driver for both ARM32/ARM64

ARM32 and ARM64 have the same DT definitions and the same approaches.

The generic ARM cpuidle driver can be put in common for those two
architectures.

Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Acked-by: Kevin Hilman <khilman@linaro.org>
Acked-by: Rob Herring <robherring2@gmail.com>
Acked-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Tested-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
diff --git a/drivers/cpuidle/Kconfig b/drivers/cpuidle/Kconfig
index c5029c1..8c7930b 100644
--- a/drivers/cpuidle/Kconfig
+++ b/drivers/cpuidle/Kconfig
@@ -29,15 +29,10 @@
 	bool
 
 menu "ARM CPU Idle Drivers"
-depends on ARM
+depends on ARM || ARM64
 source "drivers/cpuidle/Kconfig.arm"
 endmenu
 
-menu "ARM64 CPU Idle Drivers"
-depends on ARM64
-source "drivers/cpuidle/Kconfig.arm64"
-endmenu
-
 menu "MIPS CPU Idle Drivers"
 depends on MIPS
 source "drivers/cpuidle/Kconfig.mips"