mfd: wcd9xxx: Increase codec max regulators

Increase codec max regulators count by one as wcd9330 codec has
stereo speakers and require an additional on-demand supply.

Change-Id: Ie01b233d555a925687fa5c99363664206cf1b197
Signed-off-by: Sudheer Papothi <spapothi@codeaurora.org>