regulator: fix kernel-doc warnings in header files

Fix kernel-doc warnings in regulator header files:

Warning(..//include/linux/regulator/machine.h:140): No description found for parameter 'ramp_disable'
Warning(..//include/linux/regulator/driver.h:279): No description found for parameter 'linear_ranges'
Warning(..//include/linux/regulator/driver.h:279): No description found for parameter 'n_linear_ranges'

Signed-off-by: Randy Dunlap <rdunlap@infradead.org>
Signed-off-by: Mark Brown <broonie@linaro.org>
diff --git a/include/linux/regulator/machine.h b/include/linux/regulator/machine.h
index 730e638..0b08d05 100644
--- a/include/linux/regulator/machine.h
+++ b/include/linux/regulator/machine.h
@@ -85,6 +85,7 @@
  *           bootloader then it will be enabled when the constraints are
  *           applied.
  * @apply_uV: Apply the voltage constraint when initialising.
+ * @ramp_disable: Disable ramp delay when initialising or when setting voltage.
  *
  * @input_uV: Input voltage for regulator when supplied by another regulator.
  *