ARM: dts: remove stih415-clks.h

Since v4.8, STiH415/416 clock support has
been removed [1], these platform doesn't boot.
We can remove DTS files related to these socs.

[1] https://patchwork.kernel.org/patch/9157571/Signed-off-by: Patrice Chotard <patrice.chotard@st.com>

include/dt-bindings/clock/stih415-clks.h

-/*
- * This header provides constants clk index STMicroelectronics
- * STiH415 SoC.
- */
-#ifndef _CLK_STIH415
-#define _CLK_STIH415
-
-/* CLOCKGEN A0 */
-#define CLK_ICN_REG		0
-#define CLK_ETH1_PHY		4
-
-/* CLOCKGEN A1 */
-#define CLK_ICN_IF_2		0
-#define CLK_GMAC0_PHY		3
-
-#endif