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>

Use correct spelling of "U-Boot"

Correct spelling of "U-Boot" shall be used in all written text
(documentation, comments in source files etc.).

Signed-off-by: Bin Meng <bmeng.cn@gmail.com>
Reviewed-by: Heiko Schocher <hs@denx.de>
Reviewed-by: Simon Glass <sjg@chromium.org>
Reviewed-by: Minkyu Kang <mk7.kang@samsung.com>

Add GPL-2.0+ SPDX-License-Identifier to source files

Signed-off-by: Wolfgang Denk <wd@denx.de>
[trini: Fixup common/cmd_io.c]
Signed-off-by: Tom Rini <trini@ti.com>

microblaze: Add muldi3.c which contains routines for _muldi3

Referenced arch/blackfin/lib/muldi3.c and the linux kernel.
Resolves issue seen when building u-boot for HW_MUL=0;

PLATFORM_CPPFLAGS += -mxl-soft-mul
PLATFORM_CPPFLAGS += -mno-xl-multiply-high

which resulted in error while linking to libgcc.a without mul hw (bs / m);

libgcc.a(_muldi3.o): In function `__muldi3':
.... src/gcc-4.6.2/libgcc/libgcc2.c:550: undefined reference to `_GLOBAL_OFFSET_TABLE_'

This link failure would not occur if we used gcc instead of ld directly, as
gcc will correctly use the crt's to resolve this link.

Signed-off-by: David Holsgrove <david.holsgrove@xilinx.com>
Signed-off-by: Michal Simek <michal.simek@xilinx.com>