staging: iio: tsl2583: remove redundant write to the control register in taos_probe()

taos_probe() calls i2c_smbus_write_byte() to select the control
register, however there are no subsequent calls to
i2c_smbus_read_byte(). The write call is unnecessary and is removed by
this patch.

Verified that the driver still functions correctly using a TSL2581
hooked up to a Raspberry Pi 2.

Signed-off-by: Brian Masney <masneyb@onstation.org>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>