wifi: rtw88: remove unused USB bulkout size set

Drop no longer used 'bulkout_size' of 'struct rtw_usb' as well
as related macros from usb.h and leftovers in 'rtw_usb_parse()'.
This follows commit 462c8db6 ("wifi: rtw88: usb: drop
now unnecessary URB size check").

Reviewed-by: Ping-Ke Shih <pkshih@realtek.com>
Reviewed-by: Sascha Hauer <s.hauer@pengutronix.de>
Signed-off-by: Dmitry Antipov <dmantipov@yandex.ru>
Signed-off-by: Kalle Valo <kvalo@kernel.org>
Link: https://lore.kernel.org/r/20230628072327.167196-3-dmantipov@yandex.ru