MLK-16219 pca953x_gpio: Clear the polarity invert register at init

MLK-16219 pca953x_gpio: Clear the polarity invert register at init

The pca953x_gpio driver uses default value of polarity inversion register.
For some devices like PCA9557 and MAX7310, their polarity inversion register
default value is 0xf0. So for high 4 ports, when reading their values,
the values are inverted as the actual level.

This patch clears the polarity inversion register to 0 at init. So that the port read
and write values are aligned.

Signed-off-by: Ye Li <ye.li@nxp.com>
Acked-by: Fugang Duan <fugang.duan@nxp.com>
Acked-by: Peng Fan <peng.fan@nxp.com>