Use the 32 kHz clock from S5M8767 PMIC in the S3C RTC node. Except
making the S3C RTC working, this also fixes dtbs_check warnings:
  arch/arm/boot/dts/exynos5250-spring.dt.yaml: rtc@
101e0000: clocks: [[2, 337]] is too short
  arch/arm/boot/dts/exynos5250-spring.dt.yaml: rtc@
101e0000: clock-names: ['rtc'] is too short
Signed-off-by: Krzysztof Kozlowski <krzk@kernel.org>
Link: https://lore.kernel.org/r/20200901075417.22481-10-krzk@kernel.org
  */
 
 /dts-v1/;
+#include <dt-bindings/clock/samsung,s2mps11.h>
 #include <dt-bindings/gpio/gpio.h>
 #include <dt-bindings/interrupt-controller/irq.h>
 #include <dt-bindings/input/input.h>
                                                 <1200000>, <1200000>,
                                                 <1200000>, <1200000>;
 
-               clocks {
+               s5m8767_osc: clocks {
                        compatible = "samsung,s5m8767-clk";
                        #clock-cells = <1>;
                        clock-output-names = "en32khz_ap",
        };
 };
 
+&rtc {
+       status = "okay";
+       clocks = <&clock CLK_RTC>, <&s5m8767_osc S2MPS11_CLK_AP>;
+       clock-names = "rtc", "rtc_src";
+};
+
 &sd1_bus4 {
        samsung,pin-drv = <EXYNOS4_PIN_DRV_LV1>;
 };