usb: dwc2: gadget: add bi-directional endpoint support

GHWCFG1 provides hardware configuration of each endpoint. Use
it to configure the endpoints instead of assuming all even
endpoint are OUT and all odd endpoints are IN.

Tested-by: Robert Baldyga <r.baldyga@samsung.com>
Acked-by: Paul Zimmerman <paulz@synopsys.com>
Signed-off-by: Mian Yousaf Kaukab <yousaf.kaukab@intel.com>
Signed-off-by: Felipe Balbi <balbi@ti.com>