rtl8xxxu: Switch 8723a to use new rtl8xxxu_init_queue_reserved_page() routine

This changes the pub-queue value written to REQ_RQPN, however the old
code used a hard coded minimum value assuming there would always be an
active lo-queue, even when no USB EP was found for it.

Signed-off-by: Jes Sorensen <Jes.Sorensen@redhat.com>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>