rockchip: video: vop: Fix format of fbbase in debug string

The debug string printing the device name, framebuffer address and of node
is using %lu as format for the framebuffer address, which is not so nice.
Change it to %lx.

Signed-off-by: Arnaud Patard <arnaud.patard@rtp-net.org>
Tested-by: Peter Robinson <pbrobinson@gmail.com>