board/udoo/neo/readme.txt: provide more details

This patch adds more information to the Udoo Neo's readme, e.g., UART
pins and baudrate.

Signed-off-by: Kilian Zinnecker <kilian.zinnecker@mail.de>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@bootlin.com>
(cherry picked from commit 008e37b3aeb304919a3eb4d1c47b2b4d49ec49db)
Signed-off-by: Peter Korsgaard <peter@korsgaard.com>

board/udoo/neo/readme.txt

@@ -1,12 +1,36 @@
 MX6X Udoo Neo board
-
+===================
 http://www.udoo.org/udoo-neo/
 
+Build:
+======
+
 To build a minimal support for these boards:
 
     $ make mx6sx_udoo_neo_defconfig
     $ make
 
+Files created in the output directory:
+======================================
+
+output/images
+.
+├── boot.scr
+├── imx6sx-udoo-neo-basic.dtb
+├── imx6sx-udoo-neo-extended.dtb
+├── imx6sx-udoo-neo-full.dtb
+├── rootfs.ext2
+├── rootfs.ext4 -> rootfs.ext2
+├── rootfs.tar
+├── sdcard.img
+├── SPL
+├── u-boot.bin
+├── u-boot.img
+└── zImage
+
+Creating bootable SD card:
+==========================
+
 Buildroot prepares a bootable "sdcard.img" image in the output/images/
 directory, ready to be dumped on an SD card:
 
@@ -14,3 +38,31 @@ dd if=output/images/sdcard.img of=/dev/<your-microsd-device>
 
 For details about the medium image layout, see the definition in
 board/freescale/common/imx/genimage.cfg.template_no_boot_part_spl.
+
+Booting:
+========
+
+Serial console:
+---------------
+The Udoo Neo features the serial console "UART1" on the pin header "P7". The
+Uart pins are as follows (see board labels):
+
+pin 46: rx
+pin 47: tx
+
+Baudrate for this board is 115200.
+
+Login:
+------
+Enter 'root' as login user, and the prompt is ready.
+
+Documentation:
+==============
+
+documentation link:
+-------------------
+https://www.udoo.org/docs-neo/Introduction/Introduction.html
+
+forum link:
+-----------
+https://www.udoo.org/forum/forums/udoo-neo.39/