blackfin: add spi and i2c specific get clock functions

Signed-off-by: Sonic Zhang <sonic.zhang@analog.com>
diff --git a/arch/blackfin/include/asm/clock.h b/arch/blackfin/include/asm/clock.h
index fc84fe4..59d3faa 100644
--- a/arch/blackfin/include/asm/clock.h
+++ b/arch/blackfin/include/asm/clock.h
@@ -68,10 +68,21 @@
 	return uclk;
 }
 
+extern u_long get_vco(void);
+extern u_long get_cclk(void);
+extern u_long get_sclk(void);
+
 #ifdef CGU_DIV
+extern u_long get_sclk0(void);
+extern u_long get_sclk1(void);
+extern u_long get_dclk(void);
 # define get_uart_clk get_sclk0
+# define get_i2c_clk get_sclk0
+# define get_spi_clk get_sclk0
 #else
 # define get_uart_clk get_sclk
+# define get_i2c_clk get_sclk
+# define get_spi_clk get_sclk
 #endif
 
 #endif