sb/intel/common: Make linking rtc.c conditional

Change-Id: I7321da453c0d9bb4a142c3c93103d8dc0ff416b7
Signed-off-by: Arthur Heymans <arthur@aheymans.xyz>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/33201
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Nico Huber <nico.h@gmx.de>
diff --git a/src/southbridge/intel/i82371eb/Kconfig b/src/southbridge/intel/i82371eb/Kconfig
index 6552099..1d984a2 100644
--- a/src/southbridge/intel/i82371eb/Kconfig
+++ b/src/southbridge/intel/i82371eb/Kconfig
@@ -2,6 +2,7 @@
 	select ACPI_INTEL_HARDWARE_SLEEP_VALUES
 	select SOUTHBRIDGE_INTEL_COMMON
 	select SOUTHBRIDGE_INTEL_COMMON_SMBUS
+	select SOUTHBRIDGE_INTEL_COMMON_RTC
 	bool
 
 config BOOTBLOCK_SOUTHBRIDGE_INIT