Add LEDs blink_set() support to qca8k Switch Family.
These LEDs support hw accellerated blinking at a fixed rate
of 4Hz.
Reject any other value since not supported by the LEDs switch.
Signed-off-by: Christian Marangi <ansuelsmth@xxxxxxxxx>
Reviewed-by: Andrew Lunn <andrew@xxxxxxx>
Acked-by: Pavel Machek <pavel@xxxxxx>