rockchip: clk: rk3288: handle clk_enable requests for GMAC

rockchip: clk: rk3288: handle clk_enable requests for GMAC

Since b0ba1e7e9d9b9441a18048ec67a3b3100c096975
(rockchip: clk: rk3288: add clk_enable function and support USB HOST0/HSIC)
Ethernet no longer probes on RK3288.

Add no-ops for GMAC clocks observed to be requested which match the
clk_enable cases in RK3368 and RK3399.

Signed-off-by: Jonathan Gray <[email protected]>
Cc: Wadim Egorov <[email protected]>
Cc: Philipp Tomsich <[email protected]>
Acked-by: Philipp Tomsich <[email protected]>
Reviewed-by: Philipp Tomsich <[email protected]>