board/beaglebone: fix boot on BeagleBone Black

Commit 68b5b79b2f has set the getty port to the default console but left
"ttyO0" in bootargs, in the U-Boot environment. Use "ttyS0", instead.

Also set loadaddr to 0x82000000 and fdtaddr to 0x88000000, replacing the
values that were valid for the ancient U-Boot and Linux pre-installed on
old boards but cause boot hangs with the current versions.

Signed-off-by: Carlos Santos <unixmania@gmail.com>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@bootlin.com>
(cherry picked from commit 6458b154a2064267116fe14b50315b3b55d47e50)
Signed-off-by: Peter Korsgaard <peter@korsgaard.com>

board/beaglebone/uEnv.txt

@@ -3,6 +3,9 @@ devtype=mmc
 bootdir=
 bootfile=zImage
 bootpartition=mmcblk0p2
+console=ttyS0,115200n8
+loadaddr=0x82000000
+fdtaddr=0x88000000
 set_mmc1=if test $board_name = A33515BB; then setenv bootpartition mmcblk1p2; fi
-set_bootargs=setenv bootargs console=ttyO0,115200n8 root=/dev/${bootpartition} rw rootfstype=ext4 rootwait
+set_bootargs=setenv bootargs console=${console} root=/dev/${bootpartition} rw rootfstype=ext4 rootwait
 uenvcmd=run set_mmc1; run set_bootargs;run loadimage;run loadfdt;printenv bootargs;bootz ${loadaddr} - ${fdtaddr}