SPDX: Correct SPDX tags from recent xilinx merge

Correct the SPDX tag format.

Fixes: 3b52847a ("Merge tag 'xilinx-for-v2018.07' of git://www.denx.de/git/u-boot-microblaze"

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