mtd: spi-nor: EXPORT symbols which could be used by module drivers

Fix errors like this:

    ERROR: "spi_nor_ids" [drivers/mtd/devices/m25p80.ko] undefined!
    ERROR: "spi_nor_scan" [drivers/mtd/devices/m25p80.ko] undefined!
    make[1]: *** [__modpost] Error 1
    make: *** [modules] Error 2
Signed-off-by: Brian Norris <computersforpeace@gmail.com>

drivers/mtd/spi-nor/spi-nor.c

@@ -584,6 +584,7 @@ const struct spi_device_id spi_nor_ids[] = {
 	{ "cat25128", CAT25_INFO(2048, 8, 64, 2, SPI_NOR_NO_ERASE | SPI_NOR_NO_FR) },
 	{ },
 };
+EXPORT_SYMBOL_GPL(spi_nor_ids);
 
 static const struct spi_device_id *spi_nor_read_id(struct spi_nor *nor)
 {
@@ -1081,6 +1082,7 @@ int spi_nor_scan(struct spi_nor *nor, const struct spi_device_id *id,
 				mtd->eraseregions[i].numblocks);
 	return 0;
 }
+EXPORT_SYMBOL_GPL(spi_nor_scan);
 
 const struct spi_device_id *spi_nor_match_id(char *name)
 {
@@ -1093,6 +1095,7 @@ const struct spi_device_id *spi_nor_match_id(char *name)
 	}
 	return NULL;
 }
+EXPORT_SYMBOL_GPL(spi_nor_match_id);
 
 MODULE_LICENSE("GPL");
 MODULE_AUTHOR("Huang Shijie <shijie8@gmail.com>");