p54: fix wmm queue settings

This patch fixes a regression (introduced by
"p54: more definitions form lmac_longbow.h and pda.h")

It turned out that the "ret" variable wasn't initialized and
this caused the following warnings/errors to appear:

wmaster1: failed to set TX queue parameters for queue 2
wmaster1: failed to set TX queue parameters for queue 3
wmaster1: failed to set TX queue parameters for queue 1
wmaster1: failed to set TX queue parameters for queue 0

Signed-off-by: Christian Lamparter <chunkeey@web.de>
Signed-off-by: John W. Linville <linville@tuxdriver.com>