Correct SPL uses of CMD_CLK

This converts 7 usages of this option to the non-SPL form, since there is
no SPL_CMD_CLK defined in Kconfig

Signed-off-by: Simon Glass <sjg@chromium.org>
Reviewed-by: Sean Anderson <seanga2@gmail.com>
diff --git a/drivers/clk/imx/clk-imx8.h b/drivers/clk/imx/clk-imx8.h
index 68ad675..6e850ba 100644
--- a/drivers/clk/imx/clk-imx8.h
+++ b/drivers/clk/imx/clk-imx8.h
@@ -9,7 +9,7 @@
 	const char *name;
 };
 
-#if CONFIG_IS_ENABLED(CMD_CLK)
+#if IS_ENABLED(CONFIG_CMD_CLK)
 extern struct imx8_clks imx8_clk_names[];
 extern int num_clks;
 #endif