mtd: spi-nor: core: Shrink the storage size of the flash_info's addr_nbytes

The maximum number of address bytes in SPI NOR is 4. Shrink the storage
size of the flash_info's addr_nbytes.
Signed-off-by: Tudor Ambarus <tudor.ambarus@microchip.com>
Reviewed-by: Michael Walle <michael@walle.cc>
Reviewed-by: Pratyush Yadav <p.yadav@ti.com>
Link: https://lore.kernel.org/r/20220725092505.446315-3-tudor.ambarus@microchip.com

drivers/mtd/spi-nor/core.h

@@ -487,7 +487,7 @@ struct flash_info {
 	unsigned sector_size;
 	u16 n_sectors;
 	u16 page_size;
-	u16 addr_nbytes;
+	u8 addr_nbytes;
 
 	bool parse_sfdp;
 	u16 flags;