net: qed: address kernel-doc warnings

Get rid of the kernel-doc warnings when building with W=1+ by
rewriting the problematic doc comments according to the
recommended format and style.

Note that this only fixes problems found in C source files,
headers aren't in scope for now.

Signed-off-by: Alexander Lobakin <alobakin@marvell.com>
Signed-off-by: Igor Russkikh <irusskikh@marvell.com>
Signed-off-by: David S. Miller <davem@davemloft.net>