libusbg: Allow to store error information in usbg_gadget
libusbg: Allow to store error information in usbg_gadget

If error occurred during parsing user should have
an oportunity to get details about place and type
of error.

Signed-off-by: Krzysztof Opasiak <8064eda6f94b3817252b7d7649cf754592f63500@samsung.com>

pszewczyk/libusbg,pszewczyk/libusbg