The code for retrieving QH for particular endpoint is hard to understand, moreover it's duplicated all over the driver. Move the code into single nice and documented function. Signed-off-by: Marek Vasut <marex@denx.de> Cc: Fabio Estevam <fabio.estevam@freescale.com> Cc: Lei Wen <leiwen@marvell.com> Cc: Otavio Salvador <otavio@ossystems.com.br> Cc: Stefano Babic <sbabic@denx.de>