staging: r8188eu: use ieee80211 helper to read the qos tid

Replace the driver-specific GetPriority macro with ieee80211_get_tid,
which does exactly the same thing.

Signed-off-by: Martin Kaiser <martin@kaiser.cx>
Link: https://lore.kernel.org/r/20220413200742.276806-2-martin@kaiser.cx


Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>