Currently there is no logical place to put the code that prepares the
splash image data. The splash image data should be ready in memory
before bmp_display() is called, and after the environment is ready
(since lcd.c looks for the splash image in an address specified by
the environment variable "splashimage").

Our window of opportunity in board_init_r() is therefore: between
env_relocate() and bmp_display(), and from the available options
only the lcd related functions in drv_lcd_init() seem appropriate
for such lcd oriented code.

Add the option to prepare the splash image data in lcd_logo() right
before it is sent to be displayed.

Cc: Anatolij Gustschin <agust@denx.de>
Cc: Jeroen Hofstee <jeroen@myspectrum.nl>
Signed-off-by: Nikita Kiryanov <nikita@compulab.co.il>
Signed-off-by: Igor Grinberg <grinberg@compulab.co.il>