[JFFS2] Use a single config option for write buffer support

This patch replaces the current CONFIG_JFFS2_FS_NAND, CONFIG_JFFS2_FS_NOR_ECC
and CONFIG_JFFS2_FS_DATAFLASH with a single configuration option -
CONFIG_JFFS2_FS_WRITEBUFFER.

The only functional change of this patch is that the slower div/mod
calculations for SECTOR_ADDR(), PAGE_DIV() and PAGE_MOD() are now always
used when CONFIG_JFFS2_FS_WRITEBUFFER is enabled.

Signed-off-by: Andrew Victor <andrew@sanpeople.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
diff --git a/fs/jffs2/nodelist.h b/fs/jffs2/nodelist.h
index a4864d0..8c12283 100644
--- a/fs/jffs2/nodelist.h
+++ b/fs/jffs2/nodelist.h
@@ -7,7 +7,7 @@
  *
  * For licensing information, see the file 'LICENCE' in this directory.
  *
- * $Id: nodelist.h,v 1.126 2004/11/19 15:06:29 dedekind Exp $
+ * $Id: nodelist.h,v 1.127 2005/02/09 09:23:53 pavlov Exp $
  *
  */
 
@@ -462,7 +462,7 @@
 /* erase.c */
 void jffs2_erase_pending_blocks(struct jffs2_sb_info *c, int count);
 
-#ifdef CONFIG_JFFS2_FS_NAND
+#ifdef CONFIG_JFFS2_FS_WRITEBUFFER
 /* wbuf.c */
 int jffs2_flush_wbuf_gc(struct jffs2_sb_info *c, uint32_t ino);
 int jffs2_flush_wbuf_pad(struct jffs2_sb_info *c);