clk: at91: propagate rate change on system clks

System clks are just gates, and thus do not provide any rate operations.
Authorize clk rate change to be propagated to system clk parents.

Signed-off-by: Boris BREZILLON <b.brezillon@overkiz.com>
Signed-off-by: Mike Turquette <mturquette@linaro.org>

drivers/clk/at91/clk-system.c

@@ -84,7 +84,7 @@ at91_clk_register_system(struct at91_pmc *pmc, const char *name,
 	 * (see drivers/memory) which would request and enable the ddrck clock.
 	 * When this is done we will be able to remove CLK_IGNORE_UNUSED flag.
 	 */
-	init.flags = CLK_IGNORE_UNUSED;
+	init.flags = CLK_SET_RATE_PARENT | CLK_IGNORE_UNUSED;
 
 	sys->id = id;
 	sys->hw.init = &init;