ice.4: Zap registered mark from document descr

Document descriptions for device drivers always contain registered
trademarks of the manufacturers, but this is not a place for the
registered mark symbol. While here, remove another useless symbol,
the hyphen in the first line comment.

MFC after: 3 days

(cherry picked from commit 6720975ba0c5b821ea0e889457737a3e2692125a)