regulator: palmas-pmic: doc: remove ti,tstep

commit 28d1e8cd671a53d6b4f967abbbc2a55f7bd333f6
(regulator: palma: add ramp delay support through regulator constraints)

Removed the regulator's ti,step option from driver without updating the
documentation.

So, remove from documentation and example as well.

Signed-off-by: Nishanth Menon <nm@ti.com>
Signed-off-by: Mark Brown <broonie@linaro.org>

Documentation/devicetree/bindings/regulator/palmas-pmic.txt

@@ -33,7 +33,6 @@ Optional nodes:
 	       ti,roof-floor - control voltage selection by pin(boolean)
 	       ti,mode-sleep - mode to adopt in pmic sleep 0 - off, 1 - auto,
 	       2 - eco, 3 - forced pwm
-	       ti,tstep - slope control 0 - Jump, 1 10mV/us, 2 5mV/us, 3 2.5mV/us
 	       ti,smps-range - OTP has the wrong range set for the hardware so override
 	       0 - low range, 1 - high range.
 
@@ -59,7 +58,6 @@ pmic {
 			ti,warm-reset;
 			ti,roof-floor;
 			ti,mode-sleep = <0>;
-			ti,tstep = <0>;
 			ti,smps-range = <1>;
 		};