sf: sst: setup read func

The previous unification patch missed setting up the sst read func.

Signed-off-by: Mike Frysinger <vapier@gentoo.org>

drivers/mtd/spi/sst.c

@@ -255,6 +255,7 @@ spi_flash_probe_sst(struct spi_slave *spi, u8 *idcode)
 
 	stm->flash.write = sst_write;
 	stm->flash.erase = sst_erase;
+	stm->flash.read = spi_flash_cmd_read_fast;
 	stm->flash.sector_size = SST_SECTOR_SIZE;
 	stm->flash.size = stm->flash.sector_size * params->nr_sectors;