rtc: sun6i: extend test coverage

COMPILE_TEST was wrongly placed, move it to the "depends on" line.
Also depend on COMMON_CLK as the driver now needs it to be properly
compiled.
Signed-off-by: Alexandre Belloni <alexandre.belloni@free-electrons.com>

drivers/rtc/Kconfig

@@ -1435,8 +1435,9 @@ config RTC_DRV_SUN4V
 
 config RTC_DRV_SUN6I
 	bool "Allwinner A31 RTC"
-	default MACH_SUN6I || MACH_SUN8I || COMPILE_TEST
-	depends on ARCH_SUNXI
+	default MACH_SUN6I || MACH_SUN8I
+	depends on COMMON_CLK
+	depends on ARCH_SUNXI || COMPILE_TEST
 	help
 	  If you say Y here you will get support for the RTC found in
 	  some Allwinner SoCs like the A31 or the A64.