As stated in [1], dma_set_mask() with a 64-bit mask never fails if
dev->dma_mask is non-NULL.
So, if it fails, the 32 bits case will also fail for the same reason.

Moreover, dma_set_mask_and_coherent() returns 0 or -EIO, so the return
code of the function can be used directly.

Finally, inline bnx2x_set_coherency_mask() because it is now only a wrapper
for a single dma_set_mask_and_coherent() call.

Simplify code and remove some dead code accordingly.

[1]: https://lkml.org/lkml/2021/6/7/398Signed-off-by: Christophe JAILLET <christophe.jaillet@wanadoo.fr>
Link: https://lore.kernel.org/r/29608a525876afddceabf8f11b2ba606da8748fc.1641730747.git.christophe.jaillet@wanadoo.frSigned-off-by: Jakub Kicinski <kuba@kernel.org>