SPDX: Convert all of our single license tags to Linux Kernel style

When U-Boot started using SPDX tags we were among the early adopters and
there weren't a lot of other examples to borrow from. So we picked the
area of the file that usually had a full license text and replaced it
with an appropriate SPDX-License-Identifier: entry. Since then, the
Linux Kernel has adopted SPDX tags and they place it as the very first
line in a file (except where shebangs are used, then it's second line)
and with slightly different comment styles than us.

In part due to community overlap, in part due to better tag visibility
and in part for other minor reasons, switch over to that style.

This commit changes all instances where we have a single declared
license in the tag as both the before and after are identical in tag
contents. There's also a few places where I found we did not have a tag
and have introduced one.

Signed-off-by: Tom Rini <trini@konsulko.com>

mvebu: axp: Rename MV_DDR_32BIT to CONFIG_DDR_32BIT

This should make it clear that this symbol is meant to be defined by
board headers.

Signed-off-by: Phil Sutter <phil@nwl.cc>
Acked-by: Stefan Roese <sr@denx.de>
Reviewed-by: Tom Rini <trini@konsulko.com>

arm: mvebu: drivers/ddr: Move Armada XP DDR init code into new directory

With the upcoming addition of the Armada 38x DDR support, which is not
compatible to the Armada XP DDR init code, we need to introduce a new
directory infrastructure. To support multiple Marvell DDR controller.

This will be the new structure:

drivers/ddr/marvell/axp
Supporting Armada XP (AXP) devices (and perhaps Armada 370)

drivers/ddr/marvell/a38x
Supporting Armada 38x devices (and perhaps Armada 39x)

Signed-off-by: Stefan Roese <sr@denx.de>