arm64: defconfig: enable I2C_PXA

Now that the Armada 37xx SoCs support the i2c pxa driver, enable it by
default.

Signed-off-by: Gregory CLEMENT <gregory.clement@free-electrons.com>

arch/arm64/configs/defconfig

@@ -250,6 +250,7 @@ CONFIG_I2C_DESIGNWARE_PLATFORM=y
 CONFIG_I2C_IMX=y
 CONFIG_I2C_MESON=y
 CONFIG_I2C_MV64XXX=y
+CONFIG_I2C_PXA=y
 CONFIG_I2C_QUP=y
 CONFIG_I2C_RK3X=y
 CONFIG_I2C_TEGRA=y