ath10k: snoc: skip regulator operations

The regulator operations is trying to set a voltage to a fixed value, by
giving some wiggle room. But some board designs specifies regulator
voltages outside this limited range. One such example is the Lenovo Yoga
C630, with vdd-3.3-ch0 in particular specified at 3.1V.

But consumers with fixed voltage requirements should just rely on the
board configuration to provide the power at the required level, so this
code should be removed.

Signed-off-by: Bjorn Andersson <bjorn.andersson@linaro.org>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>