Correct generic memset implementation

Signed-off-by: Chris Dearman <chris@mips.com>
diff --git a/libc/string/memset.c b/libc/string/memset.c
index ed9cdd7..41dafb2 100644
--- a/libc/string/memset.c
+++ b/libc/string/memset.c
@@ -34,10 +34,10 @@
     char*  end = q + n;
 
     for (;;) {
-        if (q < end) break; *q++ = (char) c;
-        if (q < end) break; *q++ = (char) c;
-        if (q < end) break; *q++ = (char) c;
-        if (q < end) break; *q++ = (char) c;
+        if (q >= end) break; *q++ = (char) c;
+        if (q >= end) break; *q++ = (char) c;
+        if (q >= end) break; *q++ = (char) c;
+        if (q >= end) break; *q++ = (char) c;
     }
 
   return dst;