usb: gadget: epautoconf: add endpoint capabilities flags verification

Introduce endpoint matching mechanism basing on endpoint capabilities
flags. We check if endpoint supports transfer type and direction requested
in ep descriptor. Since we have this new endpoint matching mechanism
there is no need to have old code guessing endpoint capabilities basing
on its name, so we are getting rid of it. Remove also the obsolete comment.

Signed-off-by: Robert Baldyga <r.baldyga@samsung.com>
Signed-off-by: Felipe Balbi <balbi@ti.com>