arm64: a37xx: dts: Add additional pinctrl definition

arm64: a37xx: dts: Add additional pinctrl definition

Add mmc pins, pcie pins and sdio pins definition and do these pins'
configuration for DB board and espressobin board;
Add uart2 pins configuration for DB board.

Reviewed-on: http://vgitil04.il.marvell.com:8080/40914
Reviewed-by: Wilson Ding <dingwei@marvell.com>
Tested-by: Wilson Ding <dingwei@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>