regulator: fix kernel-doc for set_consumer_device_supply

Fix kernel-doc warning for set_consumer_device_supply():

Warning(drivers/regulator/core.c:912): missing initial short description on line:
 * set_consumer_device_supply: Bind a regulator to a symbolic supply

Signed-off-by: Randy Dunlap <randy.dunlap@oracle.com>
Cc:	Liam Girdwood <lrg@slimlogic.co.uk>
Cc:	Mark Brown <broonie@opensource.wolfsonmicro.com>
Acked-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
Signed-off-by: Liam Girdwood <lrg@slimlogic.co.uk>