Support literals and DontCare in DataView targets (backport #3389) (#3390)

* Support literals and DontCare in DataView targets (#3389)

(cherry picked from commit 0f803cd8)

# Conflicts:
#	src/test/scala/chiselTests/experimental/DataView.scala

* Resolve backport conflicts

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Co-authored-by: Jack Koenig <koenig@sifive.com>