Exynos: clock: support get_mmc_clk for exynos

To get exactly clock value for mmc, support the get_mmc_clk() like
set_mmc_clk().

Signed-off-by: Jaehoon Chung <jh80.chung@samsung.com>
Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com>
Signed-off-by: Minkyu Kang <mk7.kang@samsung.com>
diff --git a/arch/arm/include/asm/arch-exynos/clk.h b/arch/arm/include/asm/arch-exynos/clk.h
index cd12323..1935b0b 100644
--- a/arch/arm/include/asm/arch-exynos/clk.h
+++ b/arch/arm/include/asm/arch-exynos/clk.h
@@ -34,6 +34,7 @@
 unsigned long get_i2c_clk(void);
 unsigned long get_pwm_clk(void);
 unsigned long get_uart_clk(int dev_index);
+unsigned long get_mmc_clk(int dev_index);
 void set_mmc_clk(int dev_index, unsigned int div);
 unsigned long get_lcd_clk(void);
 void set_lcd_clk(void);