remove effect of COTIRE_MINIMUM_NUMBER_OF_TARGET_SOURCES on unity targets

CMake/cotire.cmake

@@ -2587,10 +2587,6 @@ function (cotire_compute_unity_max_number_of_includes _target _maxIncludesVar)
 		endif()
 		list (LENGTH _sourceFiles _numberOfSources)
 		math (EXPR _maxIncludes "(${_numberOfSources} + ${_numberOfThreads} - 1) / ${_numberOfThreads}")
-		# a unity source segment must not contain less than COTIRE_MINIMUM_NUMBER_OF_TARGET_SOURCES files
-		if (_maxIncludes LESS ${COTIRE_MINIMUM_NUMBER_OF_TARGET_SOURCES})
-			set (_maxIncludes ${COTIRE_MINIMUM_NUMBER_OF_TARGET_SOURCES})
-		endif()
 	elseif (NOT _maxIncludes MATCHES "[0-9]+")
 		set (_maxIncludes 0)
 	endif()