dra7xx: Add dra72_evm_defconfig using CONFIG_DM

- Import various DT files for DRA7 / DR72x / dra72-evm from Linux Kernel
  v4.1
- Add config file for this board, enable DM and DM_GPIO

Cc: Simon Glass <sjg@chromium.org>
Signed-off-by: Tom Rini <trini@konsulko.com>
Reviewed-by: Simon Glass <sjg@chromium.org>