rtl8xxxu: Clean up llt_init() API

Remove last_tx_page argument from the llt_init() function. The
rtl8xxxu_fileops structure contains the correct TX_TOTAL_PAGE_NUM
value for the device, and rtl8xxxu_auto_llt_table() doesn't need to
know the value in the first place.

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