ARM: configs: at91_dt: enable PCA gpio expander as module

Build NXP PCA953X gpio expander as a module. These are present on some
sensor extension boards.

Signed-off-by: Eugen Hristev <eugen.hristev@microchip.com>

Author: ehristev

arch/arm/configs/at91_dt_defconfig

@@ -135,6 +135,7 @@ CONFIG_SPI_ATMEL_QUADSPI=y
 CONFIG_SPI_GPIO=y
 CONFIG_SPI_SPIDEV=m
 CONFIG_GPIO_SYSFS=y
+CONFIG_GPIO_PCA953X=m
 CONFIG_POWER_RESET=y
 CONFIG_POWER_SUPPLY=y
 # CONFIG_HWMON is not set