landlock: avoid landlock syscalls before ll_restrict

Avoid checking if Landlock is supported in ll_add_profile(), as it may
result in a warning being printed in ll_is_supported() in the next
commit.

Relates to #6078.

src/firejail/landlock.c

@@ -301,9 +301,6 @@ void ll_add_profile(int type, const char *data) {
 	assert(type < LL_MAX);
 	assert(data);
 
-	if (!ll_is_supported())
-		return;
-
 	while (*data == ' ' || *data == '\t')
 		data++;