dt-bindings: clock: rk3036: add SCLK_USB480M clock-id

Contrary to how it is implemented right now, the usb480m clock is a
controllable mux that can switch between the 24MHz oscillator and the
clock output of the usb2phy.

Add the needed clock-id to allow setting this mux from DT.

Acked-by: Conor Dooley <[e-mail]>
Signed-off-by: Heiko Stuebner <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]

include/dt-bindings/clock/rk3036-cru.h

···
 #define SCLK_MACREF		152
 #define SCLK_MACPLL		153
 #define SCLK_SFC		160
+#define SCLK_USB480M		161
 
 /* aclk gates */
 #define ACLK_DMAC2		194