[jdk17u-dev] RFR: 8292816: GPL Classpath exception missing from assemblyprefix.h

[Tyler Steele]

Backport to ensure the copyright headers for this file include the GPL exception.

-------------

Commit messages:
 - Backport 71ab5c95af28497fb31aba8ba9597da71bc4d3d5

Changes: https://git.openjdk.org/jdk17u-dev/pull/656/files
 Webrev: https://webrevs.openjdk.org/?repo=jdk17u-dev&pr=656&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8292816
  Stats: 3 lines in 1 file changed: 2 ins; 0 del; 1 mod
  Patch: https://git.openjdk.org/jdk17u-dev/pull/656.diff
  Fetch: git fetch https://git.openjdk.org/jdk17u-dev pull/656/head:pull/656

PR: https://git.openjdk.org/jdk17u-dev/pull/656