libata: fix kernel-doc param name

Fix libata kernel-doc parameter name.

Warning(linux-2.6.23-git13//drivers/ata/libata-core.c:1415): No description found for parameter 'sgl'

Signed-off-by: Randy Dunlap <randy.dunlap@oracle.com>
Signed-off-by: Jeff Garzik <jeff@garzik.org>
diff --git a/drivers/ata/libata-core.c b/drivers/ata/libata-core.c
index bbaa545..629eadb 100644
--- a/drivers/ata/libata-core.c
+++ b/drivers/ata/libata-core.c
@@ -1392,7 +1392,7 @@
  *	@tf: Taskfile registers for the command and the result
  *	@cdb: CDB for packet command
  *	@dma_dir: Data tranfer direction of the command
- *	@sg: sg list for the data buffer of the command
+ *	@sgl: sg list for the data buffer of the command
  *	@n_elem: Number of sg entries
  *	@timeout: Timeout in msecs (0 for default)
  *