mtd: spi-nor: use le32_to_cpu_array()

The driver calls le32_to_cpu() to convert the little-endian tables
to  a CPU endianness, where le32_to_cpus() should have been called.
Was going to use that one... and then discovered a whole array
converter, le32_to_cpu_array()! :-)

Signed-off-by: Sergei Shtylyov <sergei.shtylyov@cogentembedded.com>
Signed-off-by: Tudor Ambarus <tudor.ambarus@microchip.com>