drm/rockchip: dsi: Remove the unused function dsi_read()

The function dsi_read is defined in the dw-mipi-dsi-rockchip.c file, but
not called elsewhere, so remove this unused function.

drivers/gpu/drm/rockchip/dw-mipi-dsi-rockchip.c:362:19: warning: unused function 'dsi_read'.
Reported-by: Abaci Robot <abaci@linux.alibaba.com>
Link: https://bugzilla.openanolis.cn/show_bug.cgi?id=3984Signed-off-by: Jiapeng Chong <jiapeng.chong@linux.alibaba.com>
Signed-off-by: Heiko Stuebner <heiko@sntech.de>
Link: https://patchwork.freedesktop.org/patch/msgid/20230208023429.73696-1-jiapeng.chong@linux.alibaba.com

drivers/gpu/drm/rockchip/dw-mipi-dsi-rockchip.c

@@ -359,11 +359,6 @@ static inline void dsi_write(struct dw_mipi_dsi_rockchip *dsi, u32 reg, u32 val)
 	writel(val, dsi->base + reg);
 }
 
-static inline u32 dsi_read(struct dw_mipi_dsi_rockchip *dsi, u32 reg)
-{
-	return readl(dsi->base + reg);
-}
-
 static void dw_mipi_dsi_phy_write(struct dw_mipi_dsi_rockchip *dsi,
 				  u8 test_code,
 				  u8 test_data)