arm64: a37xx: dts: Correct mpp definitions

arm64: a37xx: dts: Correct mpp definitions

This patch corrects below mpp definitions for armada 3720 DB board
and ESPRESSOBin board:
- "smi" pins group is added and "smi" function is set for eth0;
- Now pcie pins are used as gpio to implement PCIe function in
  hardware, so "pcie" group function is changed to "gpio".

Reviewed-on: http://vgitil04.il.marvell.com:8080/43287
Reviewed-by: Hua Jing <jinghua@marvell.com>
Tested-by: iSoC Platform CI <ykjenk@marvell.com>
Cc: Simon Glass <sjg@chromium.org>
Cc: Stefan Roese <sr@denx.de>
Signed-off-by: Ken Ma <make@marvell.com>
Signed-off-by: Stefan Roese <sr@denx.de>