clock: max77686: Add driver for Maxim 77686 32Khz crystal oscillator.

This patch supports max77686 mfd's clock driver using common clock frame work.
max77686 has 3 clock ouputs which all are generated from crystal oscillator and
SOC can enable/disable them via I2C bus. All clocks are fixed-rate clock sources
so that it doesn't supply interface for changing clock rate.
Driver uses regmap API to communicate with internal register.

Signed-off-by: Jonghwa Lee <jonghwa3.lee@samsung.com>
Signed-off-by: Mike Turquette <mturquette@linaro.org>
diff --git a/drivers/clk/Kconfig b/drivers/clk/Kconfig
index df33b8e..bace9e9 100644
--- a/drivers/clk/Kconfig
+++ b/drivers/clk/Kconfig
@@ -47,4 +47,10 @@
           Supports clocking on ARM Reference designs Integrator/AP,
 	  Integrator/CP, RealView PB1176, EB, PB11MP and PBX.
 
+config COMMON_CLK_MAX77686
+	tristate "Clock driver for Maxim 77686 MFD"
+	depends on MFD_MAX77686
+	---help---
+	  This driver supports Maxim 77686 crystal oscillator clock. 
+
 endmenu