Fix linker error when compiling for imx53 with I2C enabled.

Signed-off-by: Guenter Gebhardt <g.gebhardt@gg-sw-systems.de>
--
diff --git a/barebox/arch/arm/mach-imx/speed-imx53.c 
b/barebox/arch/arm/mach-imx/speed-imx53.c
index 0d6ac24..a168c65 100644
--- a/barebox/arch/arm/mach-imx/speed-imx53.c
+++ b/barebox/arch/arm/mach-imx/speed-imx53.c
@@ -169,6 +169,11 @@ unsigned long imx_get_fecclk(void)
        return imx_get_ipgclk();
 }
 
+unsigned long imx_get_i2cclk(void)
+{
+       return imx_get_ipgclk();
+}
+
 unsigned long imx_get_mmcclk(void)
 {
        u32 reg, prediv, podf, rate;
--