net: libwx: Fix the size in RSS hash key population

net: libwx: Fix the size in RSS hash key population

While trying to fill a random RSS key, the size of the pointer
is being used rather than the actual size of the RSS key.

Fix by passing an appropriate value of the RSS key.
This issue was reported by static coverity analyser.

Fixes: eb4898fde1de8 ("net: libwx: add wangxun vf common api")
Signed-off-by: Chandra Mohan Sundar <chandramohan.explore@gmail.com>
Link: https://patch.msgid.link/20250814163014.613004-1-chandramohan.explore@gmail.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>