arm64: mvebu: Armada 3700: Add SPI device tree nodes

arm64: mvebu: Armada 3700: Add SPI device tree nodes

This patch adds the SPI device tree nodes that are still missing to
the Armada 3700 dts files.

Signed-off-by: Stefan Roese <sr@denx.de>
Cc: Nadav Haklai <nadavh@marvell.com>
Cc: Kostya Porotchkin <kostap@marvell.com>
Cc: Wilson Ding <dingwei@marvell.com>
Cc: Victor Gu <xigu@marvell.com>
Cc: Hua Jing <jinghua@marvell.com>
Cc: Terry Zhou <bjzhou@marvell.com>
Cc: Hanna Hawa <hannah@marvell.com>
Cc: Haim Boot <hayim@marvell.com>
Reviewed-by: Jagan Teki <jteki@openedev.com>