log: typo logl_pref in documentation

The name of structure element logl_prev is not matched by the
documentation.

%s/logl_pref/logl_prev/

Signed-off-by: Heinrich Schuchardt <xypron.glpk@gmx.de>

include/asm-generic/global_data.h

@@ -378,7 +378,7 @@ struct global_data {
 	 */
 	int logc_prev;
 	/**
-	 * @logl_pref: logging level of the previous message
+	 * @logl_prev: logging level of the previous message
 	 *
 	 * This value is used as logging level for continuation messages.
 	 */