In order to keep the logo being displayed, you can pass consoleblank=0 kernel command line during boot (from U-Boot command line prompt):
# setenv std_bootarg consoleblank=0; saveenv
Or during runtime (e.g. with a script in /etc/init.d) disable console blanking via:
# echo -e "\033[9;0]" >/dev/tty0
Console blanking can also be enabled/disabled accessing the display settings in sysfs:
# echo 0|1> /sys/devices/platform/mxc_sdc_fb.X/graphics/fbX/blank
where 0 is used to unblank and 1 to blank the screen and X is the display index.
see ESP documentation chapter 9.17.3 Devices->Multimedia support-> Console codes