CHIPS: Fix potential starvation in cfi_cmdset_0001

The patch below fixes a potential starvation issue that can arise when
there is contention on a chip during a period when a process is
currently writing to it.  The starvation is avoided by conditionally
rescheduling when the chip is left in a state usable by other processes.
Signed-off-by: NJosh Boyer <jdub@us.ibm.com>
Signed-off-by: NTom Gall <tom_gall@vnet.ibm.com>
Signed-off-by: NDavid Woodhouse <dwmw2@infradead.org>

drivers/mtd/chips/cfi_cmdset_0001.c

@@ -1691,6 +1691,11 @@ static int cfi_intelext_writev (struct mtd_info *mtd, const struct kvec *vecs,
 			if (chipnum == cfi->numchips)
 				return 0;
 		}
+
+		/* Be nice and reschedule with the chip in a usable state for other
+		   processes. */
+		cond_resched();
+
 	} while (len);
 
 	return 0;