regulator: core: silence warning: "VDD1: ramp_delay not set"

commit 73e705bf ("regulator: core: Add set_voltage_time op")

introduced a new rdev_warn() if the ramp_delay is 0.

Apparently, on omap3/twl4030 platforms with dynamic voltage
management this results in non-ending spurious messages like

[  511.143066] VDD1: ramp_delay not set
[  511.662322] VDD1: ramp_delay not set
[  513.903625] VDD1: ramp_delay not set
[  514.222198] VDD1: ramp_delay not set
[  517.062835] VDD1: ramp_delay not set
[  517.382568] VDD1: ramp_delay not set
[  520.142791] VDD1: ramp_delay not set
[  520.502593] VDD1: ramp_delay not set
[  523.062896] VDD1: ramp_delay not set
[  523.362701] VDD1: ramp_delay not set
[  526.143035] VDD1: ramp_delay not set

I have observed this on GTA04 while it is reported to occur on
N900 as well: https://bugzilla.kernel.org/show_bug.cgi?id=178371



This patch makes the warning appear only in debugging mode.

Signed-off-by: H. Nikolaus Schaller <hns@goldelico.com>
Signed-off-by: Mark Brown <broonie@kernel.org>