clk: rockchip: Remove an unused field in struct rockchip_mmc_clock

In "struct rockchip_mmc_clock", the 'id' field is unused.
Remove it.

Found with cppcheck, unusedStructMember.
Signed-off-by: Christophe JAILLET <christophe.jaillet@wanadoo.fr>
Link: https://lore.kernel.org/r/410bc0f86c7b9f1c80f8a4e9a2a028a9a6ee1ec0.1713970085.git.christophe.jaillet@wanadoo.frSigned-off-by: Heiko Stuebner <heiko@sntech.de>

drivers/clk/rockchip/clk-mmc-phase.c

@@ -14,7 +14,6 @@
 struct rockchip_mmc_clock {
 	struct clk_hw	hw;
 	void __iomem	*reg;
-	int		id;
 	int		shift;
 	int		cached_phase;
 	struct notifier_block clk_rate_change_nb;