brcmsmac: extend xmtfifo_sz array

The xmtfifo_sz array contains the queue sizes for the different core
revs. This array missed the sizes for the core rev 17 and 28. This
patch extends the array to also include these sizes and adds a warning
if no queue size is stored in the array for the given core rev.

Signed-off-by: Hauke Mehrtens <hauke@hauke-m.de>
Acked-by: Arend van Spriel <arend@broadcom.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>