iio: adc: qcom-spmi-adc5: Add missing VCOIN/GPIO[134] channels

iio: adc: qcom-spmi-adc5: Add missing VCOIN/GPIO[134] channels

These channels are specified in downstream kernels [1] and actively used
by e.g. the Sony Seine platform on the SM6125 SoC.  Note that GPIO2
isn't used on this platform and, while the definition downstream is
identical to the other GPIOx_100K_PU definitions, has been omitted for
lack of proper testing.

[1]: https://source.codeaurora.org/quic/la/kernel/msm-4.14/tree/drivers/iio/adc/qcom-spmi-adc5.c?h=LA.UM.7.11.r1-05200-NICOBAR.0#n688

Signed-off-by: Marijn Suijten <marijn.suijten@somainline.org>
Reviewed-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@somainline.org>
Link: https://lore.kernel.org/r/20220805135729.1037079-3-marijn.suijten@somainline.org
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>