arm64: defconfig: Enable rv3028 i2c rtc driver

Enable rv3028 i2c rtc driver as module. It is populated on
phyBOARD-Pollux-i.MX8M Plus.

Signed-off-by: Teresa Remmet <t.remmet@phytec.de>
Reviewed-by: Krzysztof Kozlowski <krzk@kernel.org>
Signed-off-by: Shawn Guo <shawnguo@kernel.org>