media: i2c: ds90ub960: Drop unused indirect block define

Drop the unused UB960_IND_TARGET_CSI_CSIPLL_REG_1 define. It does not
even match to any block in the more recent documents, so it's possible
it is not only unused but also wrong.

Reviewed-by: Jai Luthra <jai.luthra@ideasonboard.com>
Signed-off-by: Tomi Valkeinen <tomi.valkeinen@ideasonboard.com>
Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>