Auto startx

Add following lines in "/etc/modprobe.d/lcd32.conf" file.

options fbtft_device name=odroidc_tft32 rotate=270 gpios=reset:116,dc:115 speed=32000000 cs=0

Add following lines in "/etc/modules" file.

spicc
fbtft_device

Create a new config file

sudo mv /etc/X11/xorg.conf /etc/X11/xorg.conf.old
sudo vi /etc/X11/xorg.conf

And then, add following lines in "/etc/X11/xorg.conf" file.

Section "Device"
    Identifier    "C fbdev"
    Driver        "fbdev"
    Option        "fbdev" "/dev/fb2"
EndSection

Reboot

sudo reboot

Auto login [16.04]

If you want auto login.
Edit /etc/lightdm/lightdm.conf file to enable auto-login: (password: odroid) 

odroid@odroid:~$ sudo vi /etc/lightdm/lightdm.conf
[sudo] password for odroid: 
odroid@odroid:~$ cat /etc/lightdm/lightdm.conf 
[SeatDefaults]
autologin-user=odroid
autologin-user-timeout=0
odroid@odroid:~$

If it doesn't work, edit /usr/share/lightdm/lightdm.conf.d/60-lightdm-gtk-greeter.conf file to add below three lines. 

[SeatDefaults]
greeter-session=lightdm-gtk-greeter
autologin-user=odroid