sf: Discover the bank addr commands

Bank/Extended addr commands are specific to particular
flash vendor so discover them based on the idocode0.

Assign the discovered bank commands to spi_flash members
so-that the bank read/write will use their specific operations.

Signed-off-by: Jagannadha Sutradharudu Teki <jaganna@xilinx.com>
diff --git a/include/spi_flash.h b/include/spi_flash.h
index 3b6a44e..38587c2 100644
--- a/include/spi_flash.h
+++ b/include/spi_flash.h
@@ -38,6 +38,10 @@
 	u32		page_size;
 	/* Erase (sector) size */
 	u32		sector_size;
+	/* Bank read cmd */
+	u8		bank_read_cmd;
+	/* Bank write cmd */
+	u8		bank_write_cmd;
 
 	void *memory_map;	/* Address of read-only SPI flash access */
 	int		(*read)(struct spi_flash *flash, u32 offset,