sh: cpufreq: Fix driver dependencies and flag as broken.

This is only supported on SH-4, so don't expose it for the other
CPUs. Additionally, it's suffered some bitrot, so add a BROKEN
dependency as well until we fix it up.

Signed-off-by: Paul Mundt <lethal@linux-sh.org>
diff --git a/arch/sh/Kconfig b/arch/sh/Kconfig
index 3ac6db2..848a38b 100644
--- a/arch/sh/Kconfig
+++ b/arch/sh/Kconfig
@@ -474,7 +474,7 @@
 
 config SH_CPU_FREQ
 	tristate "SuperH CPU Frequency driver"
-	depends on CPU_FREQ
+	depends on CPU_FREQ && CPU_SH4 && BROKEN
 	select CPU_FREQ_TABLE
 	help
 	  This adds the cpufreq driver for SuperH. At present, only