Do include asn1.h in error.c

When generate_errors.pl was first written, there was no asn1.h. But
now there is one and it does not need any special treatment.

Signed-off-by: Gilles Peskine <Gilles.Peskine@arm.com>
diff --git a/scripts/generate_errors.pl b/scripts/generate_errors.pl
index 64d3c86..1e1dd0e 100755
--- a/scripts/generate_errors.pl
+++ b/scripts/generate_errors.pl
@@ -101,7 +101,6 @@
 
     my $include_name = $module_name;
     $include_name =~ tr/A-Z/a-z/;
-    $include_name = "" if ($include_name eq "asn1");
 
     # Fix faulty ones
     $include_name = "net_sockets" if ($module_name eq "NET");