omap3: cm-t35: extract the splash code from board

omap3: cm-t35: extract the splash code from board

The splash screen loading code can be reused by other compulab boards.
For now extract it to a common location for further reuse.

This also switches the splash code dependency from CONFIG_LCD to
CONFIG_SPLASH_SCREEN as it should normally be.

In addition this patch fixes the accidental dependency of the
get_board_mem_timings() function on CONFIG_LCD, by just moving the
splash code and leaving the above function intact.

Signed-off-by: Igor Grinberg <[email protected]>
Reviewed-by: Tom Rini <[email protected]>