cpufreq: arm: Kconfig: Add i.MX7 to supported SoC for ARM_IMX_CPUFREQ_DT

Since commit a5a9dffc ("ARM: imx: Switch imx7d to imx-cpufreq-dt
for speed-grading") i.MX7 uses this driver as well. Add it to the
description text.
Signed-off-by: Alexander Stein <alexander.stein@ew.tq-group.com>
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>

drivers/cpufreq/Kconfig.arm

@@ -124,8 +124,8 @@ config ARM_IMX_CPUFREQ_DT
 	tristate "Freescale i.MX8M cpufreq support"
 	depends on ARCH_MXC && CPUFREQ_DT
 	help
-	  This adds cpufreq driver support for Freescale i.MX8M series SoCs,
-	  based on cpufreq-dt.
+	  This adds cpufreq driver support for Freescale i.MX7/i.MX8M
+	  series SoCs, based on cpufreq-dt.
 
 	  If in doubt, say N.