[MTD] OneNAND: Reduce internal BufferRAM operations

It use blockpage instead of a pair (block, page). It can also cover a small chunk access. 0x00, 0x20, 0x40 and so on.

And in JFFS2 behavior, sometimes it reads two pages alternatively.
e.g., It first reads A page, B page and A page.
So we check another bufferram to find requested page.

Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com>

include/linux/mtd/onenand.h

@@ -42,14 +42,10 @@ typedef enum {
 
 /**
  * struct onenand_bufferram - OneNAND BufferRAM Data
- * @block:		block address in BufferRAM
- * @page:		page address in BufferRAM
- * @valid:		valid flag
+ * @blockpage:		block & page address in BufferRAM
  */
 struct onenand_bufferram {
-	int block;
-	int page;
-	int valid;
+	int	blockpage;
 };
 
 /**