dt-bindings: clock: replace a maintainer for rockchip,rk3399-cru.yaml

With the rk3399 cru YAML conversion the original text author was
somehow added as a maintainer, but who's currently no longer involved
on the subject. Replace this position with the Rockchip clock maintainer
on her request.

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

Documentation/devicetree/bindings/clock/rockchip,rk3399-cru.yaml

···
 title: Rockchip RK3399 Clock and Reset Unit
 
 maintainers:
-  - Xing Zheng <[e-mail]>
+  - Elaine Zhang <[e-mail]>
   - Heiko Stuebner <[e-mail]>
 
 description: |