inpsymt.c, use "Daniel J. Bernstein" hash function

instead of a simple sum.

just for note,
there is a wealth of newer hash functions.

For example "The FNV Non-Cryptographic Hash Algorithm"
from http://tools.ietf.org/html/draft-eastlake-fnv-03

src/spicelib/parser/inpsymt.c

@@ -273,10 +273,11 @@ void INPtabEnd(INPtables * tab)
 
 static int hash(char *name, int tsize)
 {
-    char *s;
+    unsigned int hash = 5381;
-    register int i = 0;
+    char c;
 
-    for (s = name; *s; s++)
+    while ((c = *name++) != '\0')
-        i += *s;
+        hash = (hash * 33) ^ (unsigned) c;
-    return (i % tsize);
+
+    return (int) (hash % (unsigned) tsize);
 }