Don't search for IMPORTED_LOCATION of INTERFACE_LIBRARY (14636)

The INTERFACE_LIBRARY type does not have any LOCATION at all, so
return early from GetMappedConfig. GetMappedConfig is called from
two locations, one of which already pre-checks the INTERFACE_LIBRARY
case. Remove that pre-check and handle that case inside the method
instead.
Merge topic 'fix-INTERFACE-mapped-config' into next

31ca983 Don't search for IMPORTED_LOCATION of INTERFACE_LIBRARY (14636)
FindFreetype: Detect version string with Freetype 2.5
Merge topic 'FindFreetype-2.5' into next

bc49d82 FindFreetype: Detect version string with Freetype 2.5