regulator: Fix module desciption for tps65910 regulator

Fix the module desciption and also update Kconfig to include supporting
tps65911 chip.

Signed-off-by: Axel Lin <axel.lin@gmail.com>
Acked-by: Laxman Dewangan <ldewangan@nvidia.com>
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>