mtd: spi-nor: core: Move spi_nor_set_addr_width() in spi_nor_setup()

spi_nor_setup() configures the SPI NOR memory. Setting the addr width
is too a configuration, hence we can move the spi_nor_set_addr_width()
in spi_nor_setup().

Signed-off-by: Tudor Ambarus <tudor.ambarus@microchip.com>
Reviewed-by: Pratyush Yadav <p.yadav@ti.com>
Reviewed-by: Michael Walle <michael@walle.cc>
Link: https://lore.kernel.org/r/20211207140254.87681-11-tudor.ambarus@microchip.com