i965: Torch public intel_batchbuffer_emit_dword/float helpers.

intel_batchbuffer_emit_float is dead code, it should go.

intel_batchbuffer_emit_dword only had one user, which had bungled using
them by forgetting to call intel_batchbuffer_require_space first.  So it
seems wise to delete these unsafe helpers.

Cc: mesa-stable@lists.freedesktop.org
Reviewed-by: Jason Ekstrand <jason@jlekstrand.net>
(cherry picked from commit be144e25)