media: i2c: st-vgxy61: remove redundant initialization of pointer mode

The pointer mode is being initialized with a value that is never
read, it is being re-assigned later on. The initialization is
redundant and can be removed.

Cleans up clang scan build warning:
drivers/media/i2c/st-vgxy61.c:632:33: warning: Value stored to 'mode'
during its initialization is never read [deadcode.DeadStores]

Signed-off-by: Colin Ian King <colin.i.king@gmail.com>
Reviewed-by: Benjamin Mugnier <benjamin.mugnier@foss.st.com>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>