video: ipuv3: fix framebuffer base address init with multiple IPUs

Since commit 7812bbdc ("video: Correctly handle multiple
framebuffers") the vidconsole output is missing on the primary
display on boards with two IPU units (all i.MX6Q/D based boards).
The base address of the allocated framebuffer is not correctly
programmed in the display controller. Fix it.

Reported-by: Soeren Moch <smoch@web.de>
Signed-off-by: Anatolij Gustschin <agust@denx.de>
Tested-by: Soeren Moch <smoch@web.de>