jtag/adapter: fix memory leak on usb location

At exit, free the memory allocated to hold the USB location.

Change-Id: I050701f4dc8be14fd40e8add9d0b047461fa0d1c
Signed-off-by: Antonio Borneo <borneo.antonio@gmail.com>
Reviewed-on: https://review.openocd.org/c/openocd/+/6646
Tested-by: jenkins
Reviewed-by: Tarek BOCHKATI <tarek.bouchkati@gmail.com>

src/jtag/adapter.c

@@ -120,6 +120,8 @@ int adapter_quit(void)
 			LOG_ERROR("failed: %d", result);
 	}
 
+	free(adapter_config.usb_location);
+
 	struct jtag_tap *t = jtag_all_taps();
 	while (t) {
 		struct jtag_tap *n = t->next_tap;