dm: rpi: Convert GPIO driver to driver model

Convert the BCM2835 GPIO driver to use driver model, and switch over
Raspberry Pi to use this, since it is the only board.

Signed-off-by: Simon Glass <sjg@chromium.org>
Tested-by: Stephen Warren <swarren@wwwdotorg.org>
Acked-by: Stephen Warren <swarren@wwwdotorg.org>
4 files changed