avb: move SPDX license identifiers to the first line

avb: move SPDX license identifiers to the first line

Move SPDX license identifiers to the first line, so it conforms
to license placement rule [1]:

Placement:
The SPDX license identifier in kernel files shall be added at the first
possible line in a file which can contain a comment.  For the majority
of files this is the first line, except for scripts which require the
'#!PATH_TO_INTERPRETER' in the first line.  For those scripts the SPDX
identifier goes into the second line.

[1] https://www.kernel.org/doc/Documentation/process/license-rules.rst

Reviewed-by: Mattijs Korpershoek <mkorpershoek@baylibre.com>
Signed-off-by: Igor Opaniuk <igor.opaniuk@gmail.com>
Link: https://lore.kernel.org/r/20240209192045.3961832-3-igor.opaniuk@foundries.io
Signed-off-by: Mattijs Korpershoek <mkorpershoek@baylibre.com>