clk: imx: add i.MX8MM clk driver

Add i.MX8MM clk driver support.

Signed-off-by: Peng Fan <peng.fan@nxp.com>
diff --git a/drivers/clk/imx/Makefile b/drivers/clk/imx/Makefile
index 105a58c..5ad7967 100644
--- a/drivers/clk/imx/Makefile
+++ b/drivers/clk/imx/Makefile
@@ -10,3 +10,5 @@
 obj-$(CONFIG_IMX8QXP) += clk-imx8qxp.o
 obj-$(CONFIG_IMX8QM) += clk-imx8qm.o
 endif
+obj-$(CONFIG_$(SPL_TPL_)CLK_IMX8MM) += clk-imx8mm.o clk-pll14xx.o \
+				clk-composite-8m.o