maint: Drop dead code in check-driverimpls.pl

We no longer need to special-case xenUnified, since 1dac5fbb
dropped support for that naming scheme.
Signed-off-by: NEric Blake <eblake@redhat.com>
Acked-by: NPeter Krempa <pkrempa@redhat.com>

src/check-driverimpls.pl

@@ -41,7 +41,7 @@ while (<>) {
 
             my $suffix = $impl;
             my $prefix = $impl;
-            $prefix =~ s/^([a-z]+(?:Unified)?)(.*?)$/$1/;
+            $prefix =~ s/^([a-z]+)(.*?)$/$1/;
 
             if (defined $mainprefix) {
                 if ($mainprefix ne $prefix) {
@@ -53,7 +53,7 @@ while (<>) {
             }
 
             if ($api !~ /^$mainprefix/) {
-                $suffix =~ s/^[a-z]+(?:Unified)?//;
+                $suffix =~ s/^[a-z]+//;
                 $suffix =~ s/^([A-Z]+)/lc $1/e;
             }