MIPS: ralink: Add missing clock on rt305x

The rt305x support is missing a clock required by the ethernet driver.
Signed-off-by: John Crispin <blogic@openwrt.org>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/11447/Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

arch/mips/ralink/rt305x.c

@@ -199,6 +199,7 @@ void __init ralink_clk_init(void)
 	}
 
 	ralink_clk_add("cpu", cpu_rate);
+	ralink_clk_add("sys", sys_rate);
 	ralink_clk_add("10000b00.spi", sys_rate);
 	ralink_clk_add("10000100.timer", wdt_rate);
 	ralink_clk_add("10000120.watchdog", wdt_rate);