regulator: Update comment for set_current_limit callback of struct regulator_ops

The regulators should be tending to the maximum in the available range and
consumers should specify the widest range possible.
Signed-off-by: NAxel Lin <axel.lin@gmail.com>
Signed-off-by: NMark Brown <broonie@opensource.wolfsonmicro.com>

include/linux/regulator/driver.h

@@ -58,6 +58,7 @@ enum regulator_status {
  *	regulator_desc.n_voltages.  Voltages may be reported in any order.
  *
  * @set_current_limit: Configure a limit for a current-limited regulator.
+ *                     The driver should select the current closest to max_uA.
  * @get_current_limit: Get the configured limit for a current-limited regulator.
  *
  * @set_mode: Set the configured operating mode for the regulator.