MIPS: Add basic CPUFreq options.

This patch adds basic options for MIPS CPUFreq support.

Since the cp0 timer's frequency is based on the processor clockrate it can
not be used with CPUFReq; an additional external timer is required.

Signed-off-by: Wu Zhangjin <wuzhangjin@gmail.com>
Cc: linux-mips@linux-mips.org
Cc: cpufreq@vger.kernel.org,
Cc: Dave Jones <davej@redhat.com>,
Cc: Dominik Brodowski <linux@dominikbrodowski.net>,
Cc: yanh@lemote.com
Cc: huhb@lemote.com,
Patchwork: http://patchwork.linux-mips.org/patch/659/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
diff --git a/arch/mips/kernel/cpufreq/Kconfig b/arch/mips/kernel/cpufreq/Kconfig
new file mode 100644
index 0000000..37983a1
--- /dev/null
+++ b/arch/mips/kernel/cpufreq/Kconfig
@@ -0,0 +1,27 @@
+#
+# CPU Frequency scaling
+#
+
+config MIPS_EXTERNAL_TIMER
+	bool
+
+config MIPS_CPUFREQ
+	bool
+	default y
+	depends on CPU_SUPPORTS_CPUFREQ && MIPS_EXTERNAL_TIMER
+
+if MIPS_CPUFREQ
+
+menu "CPU Frequency scaling"
+
+source "drivers/cpufreq/Kconfig"
+
+if CPU_FREQ
+
+comment "CPUFreq processor drivers"
+
+endif	# CPU_FREQ
+
+endmenu
+
+endif	# MIPS_CPUFREQ