ARM: zynq: Add missing i2c get_rate for fixing i2c SPL

The commit 'f48ef0d81aa837a33020f8d61abb3929ba613774' did break I2C
support because requesting the clock for the I2C ip-block isn't
supported during SPL.

To fixup this we add support requesting clocks for:
- i2c0
- i2c1

Signed-off-by: Hannes Schmelzer <hannes.schmelzer@br-automation.com>
Reviewed-by: Heiko Schocher <hs@denx.de>
Signed-off-by: Michal Simek <michal.simek@xilinx.com>
diff --git a/drivers/clk/clk_zynq.c b/drivers/clk/clk_zynq.c
index 482f093..b09c37d 100644
--- a/drivers/clk/clk_zynq.c
+++ b/drivers/clk/clk_zynq.c
@@ -434,6 +434,8 @@
 	case lqspi_clk ... pcap_clk:
 	case sdio0_clk ... spi1_clk:
 		return zynq_clk_get_peripheral_rate(priv, id, 0);
+	case i2c0_aper_clk ... i2c1_aper_clk:
+		return zynq_clk_get_cpu_rate(priv, cpu_1x_clk);
 	default:
 		return -ENXIO;
 	}