ARM: multi_v7_defconfig: Support RTC devices commonly used on Rockchip boards

Similar to the power management situation on Rockchip boards, there are
two common RTC setups. For boards using the RK808 chip as a PMIC that
chip also serves as the RTC, while boards using the ACT8846 typically use
the Haoyu Microelectronics HYM8563 chip as their RTC.

Signed-off-by: Sjoerd Simons <sjoerd.simons@collabora.co.uk>
Reviewed-by: Heiko Stuebner <heiko@sntech.de>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>