lsi53c895a: Update dnad when skipping MSGOUT bytes

Update not only dbc but also dnad when skipping bytes during the MSGOUT
phase.  Previously only dbc was updated which is probably wrong and
could lead to bogus message codes being read.

Tested on Linux and Windows Server 2003.

Signed-off-by: Stefan Hajnoczi <stefanha@linux.vnet.ibm.com>
Signed-off-by: Aurelien Jarno <aurelien@aurel32.net>