[mlir][bazel] Remove unsed BUILD dependencies. (#87038)
This is the second attempt of 32fcfcdc4cc1d68116438f761897953894d65fb1,
which had to be reverted.
This should be good to go now, after a number of cleanups to not expose
headers from multiple targets:
- 6e58efac16958ccb99060f4329b48737be7d8d36
- f1dff836593d4601e3ad78117df1d980d284bb9c
- 89ef3130cf16f1965475396ad3a50760558cc08a
- eb70b485a91361eee83d3744d1bd3e4c3a23692f
- 83e5a1239242d64110e3dfa96ed3889170ab96b2
- fce046ca5b7edb4c0d37a6eb580154ccb7dda966
