phy: starfive: remove unused struct 'regval'

'regval' is unused since the original
commit f8aa660 ("phy: starfive: Add mipi dphy rx support").

Remove it.

Signed-off-by: Dr. David Alan Gilbert <linux@treblig.org>
Reviewed-by: Changhuang Liang <changhuang.liang@starfivetech.com>
Link: https://lore.kernel.org/r/20240527205937.165325-1-linux@treblig.org
Signed-off-by: Vinod Koul <vkoul@kernel.org>

Author: Dr. David Alan Gilbert

drivers/phy/starfive/phy-jh7110-dphy-rx.c

@@ -46,11 +46,6 @@
 
 #define STF_MAP_LANES_NUM			6
 
-struct regval {
-	u32 addr;
-	u32 val;
-};
-
 struct stf_dphy_info {
 	/**
 	 * @maps: