Suge is telling half truths. Daz DID ghost-produce some songs on the album (Aint no fun, nikkaz and bytches, and Serial Killa), but he didn't produce the whole album by himself, and he didn't willingly sign paperwork to have his credit go to Dre.
Sam Sneed confirmed that Dre was involved in some capacity
DX: How much of
Doggystyle did you produce?
Sam Sneed: I just really brought skits to the table. I really didn’t produce anything. Like, the intro to
Snoop [Doggy Dogg]’s album, that was my idea. And then the one [skit before “Pump Pump”] where I said “fukk you bytch, I’m Sam Sneed.” That was just something [where] we was just freestyling in the studio. And then I gave Dre the records to “[Gz] Up, Hoz Down.” Yeah, I gave him a record… I was just throwing little ideas [at him], but Dre and a couple other producers really worked that album out.