usb: chipidea: udc: manage dynamic amount of tds with a linked list

Instead of having a limited number of usable tds in the udc we use a
linked list to support dynamic amount of needed tds for all special
gadget types. This improves throughput.

Signed-off-by: Michael Grzeschik <m.grzeschik@pengutronix.de>
Reviewed-by: Felipe Balbi <balbi@ti.com>
Signed-off-by: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>