sf: sst: setup read func

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

Signed-off-by: Mike Frysinger <vapier@gentoo.org>
diff --git a/drivers/mtd/spi/sst.c b/drivers/mtd/spi/sst.c
index 29bb88b..38983bd 100644
--- a/drivers/mtd/spi/sst.c
+++ b/drivers/mtd/spi/sst.c
@@ -255,6 +255,7 @@
 
 	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;