board: beacon: imx8mm: Let clock system enable UART clock

Now that the UART driver can enable the required clocks, remove
the hard-coded clock enable.  This requires a small re-order
of a couple functions.

Signed-off-by: Adam Ford <aford173@gmail.com>
Reviewed-by: Peng Fan <peng.fan@nxp.com>
diff --git a/board/beacon/imx8mm/spl.c b/board/beacon/imx8mm/spl.c
index 12013aa..93ee5b7 100644
--- a/board/beacon/imx8mm/spl.c
+++ b/board/beacon/imx8mm/spl.c
@@ -100,9 +100,6 @@
 	int ret;
 
 	arch_cpu_init();
-
-	init_uart_clk(1);
-
 	timer_init();
 
 	/* Clear the BSS. */
@@ -114,8 +111,6 @@
 		hang();
 	}
 
-	preloader_console_init();
-
 	ret = uclass_get_device_by_name(UCLASS_CLK,
 					"clock-controller@30380000",
 					&dev);
@@ -124,6 +119,7 @@
 		hang();
 	}
 
+	preloader_console_init();
 	enable_tzc380();
 
 	power_init_board();