[U-Boot] [PATCH 2/4] dm: gpio: Add a comment about not copying some drivers

[sjg at google.com]

These three drivers all use U_BOOT_DEVICE rather than device tree to
create devices, so have to do manual allocation of platform data. This is
not true for new platforms.

Add a more explicit comment so that people do not copy this approach with
new boards.

Signed-off-by: Simon Glass <sjg at chromium.org>
Reported-by: Adam Ford <aford173 at gmail.com>
---

 drivers/gpio/imx_rgpio2p.c | 5 +++++
 drivers/gpio/mxc_gpio.c    | 5 +++++
 drivers/gpio/omap_gpio.c   | 9 +++++----
 3 files changed, 15 insertions(+), 4 deletions(-)

Applied to u-boot-dm thanks!