UBI: Fastmap: Fix kernel-doc

drivers/mtd/ubi/fastmap.c:104: warning: expecting prototype for new_fm_vhdr(). Prototype was for new_fm_vbuf() instead.

Link: https://bugzilla.openanolis.cn/show_bug.cgi?id=2289Reported-by: Abaci Robot <abaci@linux.alibaba.com>
Signed-off-by: Jiapeng Chong <jiapeng.chong@linux.alibaba.com>
Signed-off-by: Richard Weinberger <richard@nod.at>

drivers/mtd/ubi/fastmap.c

@@ -93,7 +93,7 @@ size_t ubi_calc_fm_size(struct ubi_device *ubi)
 
 
 /**
- * new_fm_vhdr - allocate a new volume header for fastmap usage.
+ * new_fm_vbuf() - allocate a new volume header for fastmap usage.
  * @ubi: UBI device description object
  * @vol_id: the VID of the new header
  *