ena: Update driver version to v2.6.1

Minor version update which improves styling of a printouts, fixes
the KASAN and KMSAN kernel builds and LLQ reconfiguration after the
device reset.

Obtained from: Semihalf
MFC after: 2 weeks
Sponsored by: Amazon, Inc.

(cherry picked from commit 25b64933a48c47baef698a302fa2dc5c6e3013ea)