usb: musb: remove blackfin port

The blackfin architecture is getting removed, so we can clean up
all the special cases in the musb driver.

Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Acked-by: Aaron Wu <aaron.wu@analog.com>
Acked-by: Bin Liu <b-liu@ti.com>
Cc: Stephen Rothwell <sfr@canb.auug.org.au>
[arnd: adding in fixups from Aaron and Stephen]
Signed-off-by: Arnd Bergmann <arnd@arndb.de>

drivers/usb/musb/musbhsdma.c

@@ -235,11 +235,6 @@ static irqreturn_t dma_controller_irq(int irq, void *private_data)
 
 	int_hsdma = musb_readb(mbase, MUSB_HSDMA_INTR);
 
-#ifdef CONFIG_BLACKFIN
-	/* Clear DMA interrupt flags */
-	musb_writeb(mbase, MUSB_HSDMA_INTR, int_hsdma);
-#endif
-
 	if (!int_hsdma) {
 		musb_dbg(musb, "spurious DMA irq");