dma-buf: Couple of documentation typo fixes

Fix a couple of typos: "as" -> "has" and "int" -> "in".

Signed-off-by: Gal Pressman <galpress@amazon.com>
Link: https://lore.kernel.org/r/20200420074115.23931-1-galpress@amazon.com


Signed-off-by: Jonathan Corbet <corbet@lwn.net>