clk: shmobile: div6: use proper description in kernel doc

These variable clocks have nothing to do with MSTP gating, probably a
copy&paste leftover.
Signed-off-by: NWolfram Sang <wsa@sang-engineering.com>
Acked-by: NLaurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: NMike Turquette <mturquette@linaro.org>

drivers/clk/shmobile/clk-div6.c

@@ -23,7 +23,7 @@
 #define CPG_DIV6_DIV_MASK	0x3f
 
 /**
- * struct div6_clock - MSTP gating clock
+ * struct div6_clock - CPG 6 bit divider clock
  * @hw: handle between common and hardware-specific interfaces
  * @reg: IO-remapped register
  * @div: divisor value (1-64)