musb-new, dfu: first send request answer then call completions

comment in ep0_txstate() states:

"report completions as soon as the fifo's loaded; there's no win
 in waiting till this last packet gets acked".

This is wrong for using dfu. In the dfu usecase we must send
a PollTimeout to the host, so the host can wait until the
U-Boot Code is ready for answering new usb requests. So the
answer which contains the PollTimeout must send *before*
U-Boot calls req->complete.

The req->complete is used in the dfu case for flushing the
medium, when entering DFU_STATE_dfuMANIFEST_SYNC state.

Change-Id: Ib2941119c72761e48e15fedbdad1ecce07ae0b3d
Signed-off-by: Heiko Schocher <hs@denx.de>
Cc: Kyungmin Park <kyungmin.park@samsung.com>
Cc: Marek Vasut <marex@denx.de>
Cc: Pantelis Antoniou <panto@antoniou-consulting.com>
Acked-by: Marek Vasut <marex@denx.de>
Acked-by: Lukasz Majewski <l.majewski@samsung.com>

drivers/usb/musb-new/musb_gadget_ep0.c

@@ -576,6 +576,10 @@ static void ep0_txstate(struct musb *musb)
 	} else
 		request = NULL;
 
+	/* send it out, triggering a "txpktrdy cleared" irq */
+	musb_ep_select(musb->mregs, 0);
+	musb_writew(regs, MUSB_CSR0, csr);
+
 	/* report completions as soon as the fifo's loaded; there's no
 	 * win in waiting till this last packet gets acked.  (other than
 	 * very precise fault reporting, needed by USB TMC; possible with
@@ -588,10 +592,6 @@ static void ep0_txstate(struct musb *musb)
 			return;
 		musb->ackpend = 0;
 	}
-
-	/* send it out, triggering a "txpktrdy cleared" irq */
-	musb_ep_select(musb->mregs, 0);
-	musb_writew(regs, MUSB_CSR0, csr);
 }
 
 /*