greybus: checkpatch.pl: Mark --no-tree as default option

Don't know why, but checkpatch checks if we are running it from top of a
kernel tree or not, but then it also provides an option to suppress the
warning using --no-tree.

Instead of forcing everyone to use this every time, lets make this
behavior default.
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@google.com>

drivers/staging/greybus/scripts/checkpatch.pl

@@ -19,7 +19,7 @@ my $V = '0.32';
 use Getopt::Long qw(:config no_auto_abbrev);
 
 my $quiet = 0;
-my $tree = 1;
+my $tree = 0;
 my $chk_signoff = 1;
 my $chk_patch = 1;
 my $tst_only;