MLK-10349 ARM: dts: imx6dql: fix the clock for MIPI CSI2

Fix the clock index for cfg clock and use MACRO instead of hard-codes.

This patch fixes the following issue.
-----------------------------------------------------------
root@imx6qdlsolo:~# /unit_tests/mxc_v4l2_capture.out -d /dev/video1 1.yuv
in_width = 176, in_height = 144
out_width = 176, out_height = 144
top = 0, left = 0
mipi csi2 can not receive sensor clk!
...

ERROR: v4l2 capture: mxc_v4l_dqueue timeout enc_counter 0
VIDIOC_DQBUF failed.ERROR: v4l2 capture: VIDIOC_QBUF: buffer already queued
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Signed-off-by: Robby Cai <r63905@freescale.com>
(cherry picked from commit 6e4ee44)

arch/arm/boot/dts/imx6qdl.dtsi

@@ -1095,7 +1095,9 @@
 				compatible = "fsl,imx6q-mipi-csi2";
 				reg = <0x021dc000 0x4000>;
 				interrupts = <0 100 0x04>, <0 101 0x04>;
-				clocks = <&clks 138>, <&clks 53>, <&clks 204>;
+				clocks = <&clks IMX6QDL_CLK_HSI_TX>,
+					 <&clks IMX6QDL_CLK_EMI_SEL>,
+					 <&clks IMX6QDL_CLK_VIDEO_27M>;
 				/* Note: clks 138 is hsi_tx, however, the dphy_c
 				 * hsi_tx and pll_refclk use the same clk gate.
 				 * In current clk driver, open/close clk gate do