mtd: m25p80: Reinstate error print on unrecognized flash

Commit b34bc037 removed the
"unrecognized JEDEC id" error message, causing the probe function to
silently abort if the flash ID is unrecognized.

It is desirable to produce diagnostic output in this situation so that
the user has some idea what went wrong.
Signed-off-by: NKevin Cernekee <cernekee@gmail.com>
Signed-off-by: NArtem Bityutskiy <Artem.Bityutskiy@nokia.com>
Signed-off-by: NDavid Woodhouse <David.Woodhouse@intel.com>

drivers/mtd/devices/m25p80.c

@@ -764,6 +764,7 @@ static const struct spi_device_id *__devinit jedec_probe(struct spi_device *spi)
 			return &m25p_ids[tmp];
 		}
 	}
+	dev_err(&spi->dev, "unrecognized JEDEC id %06x\n", jedec);
 	return ERR_PTR(-ENODEV);
 }