ide: only constrain read/write requests to drive size, not other types

Commit 58ac321135a introduced a check to ide dma processing which
constrains all requests to drive size.  However, apparently, some
valid requests (like TRIM) does not fit in this constraint, and
fails in 2.1.  So check the range only for reads and writes.

Cc: qemu-stable@nongnu.org
Signed-off-by: Michael Tokarev <mjt@tls.msk.ru>
Signed-off-by: Markus Armbruster <armbru@redhat.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
