ARM: bcm2835: add simplefb DT node during bootz/m

Add a DT simple-framebuffer node to DT when booting the Linux kernel.
This will allow the kernel to inherit the framebuffer configuration from
U-Boot, and display a graphical boot console, and even run a full SW-
rendered X server.

Signed-off-by: Stephen Warren <swarren@wwwdotorg.org>
Acked-by: Simon Glass <sjg@chromium.org>
ARM: rpi_b: attempt to turn on power to SD controller

This can't be done yet: The firmware gives an error reponse to
set_power_state. See:
https://github.com/raspberrypi/firmware/issues/106

However, this isn't needed in practice, since the boot firmware must
have turned on the power itself, since it loaded U-Boot from the SD
card.

Signed-off-by: Stephen Warren <swarren@wwwdotorg.org>