mtd: fsl-quadspi: Print the error value

When displaying dev_err() messages it is useful to print the error value.

Signed-off-by: Fabio Estevam <fabio.estevam@freescale.com>
Acked-by: Han Xu <han.xu@freescale.com>
[Brian: fix up "can not" at the same time]
Signed-off-by: Brian Norris <computersforpeace@gmail.com>