video, da8xx-fb: show fb addr in bdinfo

without this patch the bdinfo command shows:
U-Boot# bd
arch_number = 0x000010DC
[...]
sp start    = 0x8EF32F20
FB base     = 0x00000000

with this patch it shows the address where the framebuffer
for this video driver start:

arch_number = 0x000010DC
[...]
sp start    = 0x8EF32F20
FB base     = 0x8EF3C788

Signed-off-by: Heiko Schocher <hs@denx.de>
Cc: Anatolij Gustschin <agust@denx.de>
Cc: Tom Rini <trini@ti.com>
Acked-by: Tom Rini <trini@ti.com>