regulator: Add input current limit support

Some regulators can limit their input current (typically annotated
as ilim). Add an op (set_input_current_limit) and a DT property +
constraint to support this.

Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>
Signed-off-by: Mark Brown <broonie@kernel.org>
diff --git a/include/linux/regulator/machine.h b/include/linux/regulator/machine.h
index 7f7d0a3..85a3b45 100644
--- a/include/linux/regulator/machine.h
+++ b/include/linux/regulator/machine.h
@@ -75,6 +75,7 @@
  *
  * @min_uA: Smallest current consumers may set.
  * @max_uA: Largest current consumers may set.
+ * @ilim_uA: Maximum input current.
  * @system_load: Load that isn't captured by any consumer requests.
  *
  * @valid_modes_mask: Mask of modes which may be configured by consumers.
@@ -113,6 +114,7 @@
 	/* current output range (inclusive) - for current control */
 	int min_uA;
 	int max_uA;
+	int ilim_uA;
 
 	int system_load;