This patch replaces all occurences of the macro DEV_OK by the actual
value 0 at the driver level. So this patch touch the files under
drivers/, include/ and samples/drivers/.
This patch is part of the effort to transition from DEV_* codes to
errno.h codes.
Change-Id: I69980ecb9755f2fb026de5668ae9c21a4ae62d1e
Signed-off-by: Andre Guedes <andre.guedes@intel.com>