pylint: set default jobs limit to use all available cpus

Since pylint-1.4 (released 2014), pylint has offered a --jobs option
to process multiple files in parallel.  Change our pylintrc default
to autodetect all available cpus.

Bug: None
Test: running `./tools/pylint.py *.py` is faster
Change-Id: Id15573bc2e8b0cfdaaa3623fc716734687d3f26c
diff --git a/tools/pylintrc b/tools/pylintrc
index 704b21b..7a82e08 100644
--- a/tools/pylintrc
+++ b/tools/pylintrc
@@ -35,8 +35,9 @@
 # usually to register additional checkers.
 load-plugins=
 
-# Use multiple processes to speed up Pylint.
-jobs=1
+# Use multiple processes to speed up Pylint.  A value of 0 autodetects available
+# processors.
+jobs=0
 
 # Allow loading of arbitrary C extensions. Extensions are imported into the
 # active Python interpreter and may run arbitrary code.