ARM: davinci: da850-evm: call regulator_has_full_constraints()

The BB expander at 0x21 i2c bus 1 fails to probe on da850-evm because
the board doesn't set has_full_constraints to true in the regulator
API.

Call regulator_has_full_constraints() at the end of board registration
just like we do in da850-lcdk and da830-evm.

Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Bartosz Golaszewski <bgolaszewski@baylibre.com>
Signed-off-by: Sekhar Nori <nsekhar@ti.com>