regulator: lp872x: Remove warning about invalid DVS GPIO

Some devices don't hook the DVS pin to a GPIO but to ground or VCC.
In those cases, it is not a problem to have no DVS GPIO provided, as the current
code will already switch to software-only DVS selection:

When the DVS GPIO is invalid, lp872x_init_dvs jumps to the set_default_dvs_mode
label, which instructs the chip not to use the DVS pin at all and do it all in
software instead (by clearing the LP8720_EXT_DVS_M bit in the
LP872X_GENERAL_CFG register).

That is reflected later in the code, when setting the bucks (the DVS pin only
applies to the bucks) by checking for the LP8720_EXT_DVS_M bit on the
LP872X_GENERAL_CFG register (in lp872x_select_buck_vout_addr) to decide whether
to use software or hardware DVS selection.

Thus, there is no need to print a warning when the DVS GPIO is invalid.

Signed-off-by: Paul Kocialkowski <[e-mail]>
Signed-off-by: Mark Brown <[e-mail]>

drivers/regulator/lp872x.c

···
 		goto set_default_dvs_mode;
 
 	gpio = dvs->gpio;
-	if (!gpio_is_valid(gpio)) {
-		dev_warn(lp->dev, "invalid gpio: %d\n", gpio);
+	if (!gpio_is_valid(gpio))
 		goto set_default_dvs_mode;
-	}
 
 	pinstate = dvs->init_state;
 	ret = devm_gpio_request_one(lp->dev, gpio, pinstate, "LP872X DVS");