mtd: fsl-quadspi: Fix the error paths

Jumping to 'map_failed' label is not correct at these points, as it misses to
disable the clocks that were previously enabled.

Jump to 'irq_failed' label instead that will correctly disable the clocks.

Signed-off-by: Fabio Estevam <fabio.estevam@freescale.com>
Acked-by: Han Xu <han.xu@freescale.com>
Signed-off-by: Brian Norris <computersforpeace@gmail.com>