dtoc: look for compatible string aliases in driver list

dtoc: look for compatible string aliases in driver list

Currently dtoc checks if the first compatible string in a dtb node
matches either a driver o driver alias name, without taking into account
any other compatible string in the list. In the case that no driver matches
the first compatible string a warning is printed and the U_BOOT_DEVICE is
not being declared correctly.

This patch adds dtoc's support for try all the compatible strings in the
dtb node, in an effort to find the correct driver.

Signed-off-by: Walter Lozano <walter.lozano@collabora.com>
Reviewed-by: Simon Glass <sjg@chromium.org>