scripts/liberty: Support new comma only syntax.

Syntax before;
```
comp_attribute blah,blah
```

Syntax after;
```
comp_attribute,blah,blah
```

Signed-off-by: Tim 'mithro' Ansell <me@mith.ro>

scripts/python-skywater-pdk/skywater_pdk/liberty.py

diff --git a/scripts/python-skywater-pdk/skywater_pdk/liberty.py b/scripts/python-skywater-pdk/skywater_pdk/liberty.py
index 617f22d..37dae20 100755
--- a/scripts/python-skywater-pdk/skywater_pdk/liberty.py
+++ b/scripts/python-skywater-pdk/skywater_pdk/liberty.py
@@ -965,8 +965,9 @@
     # Sort the attributes
     def attr_sort_key(item):
         k, v = item
-        if " " in k:
-            ktype, kvalue = k.split(" ", 1)
+
+        if "," in k:
+            ktype, kvalue = k.split(",", 1)
             sortable_kv = sortable_extracted_numbers(kvalue)
         else:
             ktype = k
@@ -1042,7 +1043,7 @@
                     o.append('%s%s : "%s";' % (INDENT*len(indent_n), k, l))
 
             else:
-                raise ValueError("Unknown %s: %r\n%s" % (k, v, indent_n))
+                raise ValueError("Unknown %s: %r\n%s" % ((ktype, kvalue, k), v, indent_n))
 
         else:
             if ktype in dtype_attribute_types: