staging: wfx: drop unused function wfx_pending_requeue()

The function wfx_pending_requeue() is not used anymore since the
commit 7a44644c ("staging: wfx: introduce
wfx_set_default_unicast_key()")

Fixes: 7a44644c ("staging: wfx: introduce wfx_set_default_unicast_key()")
Signed-off-by: Jérôme Pouiller <jerome.pouiller@silabs.com>
Link: https://lore.kernel.org/r/20200526171821.934581-4-Jerome.Pouiller@silabs.com


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