sf: probe: Add support for flag status polling

From Micron, 512MB onwards, flash requires to poll flag status
instead of read status- hence added E_FSR flag on spectific
flash parts.

Signed-off-by: Jagannadha Sutradharudu Teki <jaganna@xilinx.com>
diff --git a/include/spi_flash.h b/include/spi_flash.h
index 0d40e6c..09af55d 100644
--- a/include/spi_flash.h
+++ b/include/spi_flash.h
@@ -20,6 +20,7 @@
 /* SECT flags */
 #define SECT_4K		(1 << 1)
 #define SECT_32K		(1 << 2)
+#define E_FSR			(1 << 3)
 
 /* SST specific macros */
 #ifdef CONFIG_SPI_FLASH_SST