drm/bridge: ti-sn65dsi86: Set max register for regmap

stable inclusion
from stable-v5.10.94
commit b230114bc57a3a0c9da11a18954e747b5bb92c5d
bugzilla: https://gitee.com/openeuler/kernel/issues/I531X9

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=b230114bc57a3a0c9da11a18954e747b5bb92c5d

--------------------------------

[ Upstream commit 0b665d4a ]

Set the maximum register to 0xff so we can dump the registers for this
device in debugfs.

Fixes: a095f15c ("drm/bridge: add support for sn65dsi86 bridge driver")
Cc: Rob Clark <robdclark@chromium.org>
Cc: Douglas Anderson <dianders@chromium.org>
Cc: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: NStephen Boyd <swboyd@chromium.org>
Reviewed-by: NRobert Foss <robert.foss@linaro.org>
Signed-off-by: NRobert Foss <robert.foss@linaro.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20211215002529.382383-1-swboyd@chromium.orgSigned-off-by: NSasha Levin <sashal@kernel.org>
Signed-off-by: NZheng Zengkai <zhengzengkai@huawei.com>
Acked-by: NXie XiuQi <xiexiuqi@huawei.com>

drivers/gpu/drm/bridge/ti-sn65dsi86.c

@@ -171,6 +171,7 @@ static const struct regmap_config ti_sn_bridge_regmap_config = {
 	.val_bits = 8,
 	.volatile_table = &ti_sn_bridge_volatile_table,
 	.cache_type = REGCACHE_NONE,
+	.max_register = 0xFF,
 };
 
 static void ti_sn_bridge_write_u16(struct ti_sn_bridge *pdata,