libphobos: Fix KERNEL_VERSION condition in libphobos testsuite

A typo in the macro call meant that the #error always triggered.

libphobos/ChangeLog:

	* testsuite/lib/libphobos.exp (check_effective_target_linux_pre_2639):
	Fix KERNEL_VERSION condition.

libphobos/ChangeLog

+2020-04-29  Iain Buclaw  <ibuclaw@gdcproject.org>
+
+	* testsuite/lib/libphobos.exp (check_effective_target_linux_pre_2639):
+	Fix KERNEL_VERSION condition.
+
 2020-04-28  Iain Buclaw  <ibuclaw@gdcproject.org>
 
 	PR d/94825

libphobos/testsuite/lib/libphobos.exp

@@ -285,7 +285,7 @@ proc check_effective_target_linux_pre_2639 { } {
 
     if { [check_no_compiler_messages linux_pre_2639 assembly {
 	#include <linux/version.h>
-	#if !defined LINUX_VERSION_CODE || LINUX_VERSION_CODE < KERNEL_VERSION(2.6.39)
+	#if !defined LINUX_VERSION_CODE || LINUX_VERSION_CODE < KERNEL_VERSION(2,6,39)
 	#error Yes, it is.
 	#endif
     }] } {