cpufreq: armada-37xx: driver relies on cpufreq-dt

Armada-37xx driver registers a cpufreq-dt driver. Not having
CONFIG_CPUFREQ_DT selected leads to a silent abort during the probe.
Prevent that situation by having the former depending on the latter.

Fixes: 92ce45fb (cpufreq: Add DVFS support for Armada 37xx)
Cc: 4.16+ <stable@vger.kernel.org> # 4.16+
Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

drivers/cpufreq/Kconfig.arm

@@ -20,7 +20,7 @@ config ACPI_CPPC_CPUFREQ
 
 config ARM_ARMADA_37XX_CPUFREQ
 	tristate "Armada 37xx CPUFreq support"
-	depends on ARCH_MVEBU
+	depends on ARCH_MVEBU && CPUFREQ_DT
 	help
 	  This adds the CPUFreq driver support for Marvell Armada 37xx SoCs.
 	  The Armada 37xx PMU supports 4 frequency and VDD levels.