mb/ti/beaglebone: Init UART in early init

The console is initialized before mainboard_init, so the peripheral
should be initialized in bootblock_mainboard_early_init rather than
bootblock_mainboard_init.

Change-Id: I9f4ba29798eb0b1efea76f5ade4a234fb35a2f83
Signed-off-by: Sam Lewis <sam.vr.lewis@gmail.com>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/44380
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Patrick Georgi <pgeorgi@google.com>

src/mainboard/ti/beaglebone/bootblock.c

@@ -9,7 +9,7 @@
 
 #include "leds.h"
 
-void bootblock_mainboard_init(void)
+void bootblock_mainboard_early_init(void)
 {
 	write32(&am335x_cm_wkup->wkup_gpio0, CM_ST_SW_WKUP | CM_FCLK_EN);
 	write32(&am335x_cm_per->gpio1, CM_ST_SW_WKUP | CM_FCLK_EN);