brcmfmac: remove pending parameter from brcmf_usb_free_q

brcmf_usb_free_q is no longer called with pending=true thus this boolean
parameter is no longer needed.

Signed-off-by: Piotr Figiel <p.figiel@camlintechnologies.com>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>