utils: checkstyle.py: Fix regex string literal

The checkstyle.py patch has a fault which it identified in itself when
updating the regex string.

  --- utils/checkstyle.py
  +++ utils/checkstyle.py
  #105: : W605 invalid escape sequence '\+'
  +    diff_header_regex = re.compile('@@ -([0-9]+)(,[0-9]+)? \+([0-9]+)(,?[0-9]+)? @@')
  ---
  1 potential style issue detected, please review

This is documented further at:
  https://www.flake8rules.com/rules/W605.html

Update the string literal prefix to declare a raw byte string for the
regex parser.

Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Kieran Bingham <kieran.bingham@ideasonboard.com>

1 files changed, 1 insertions, 1 deletions

diff --git a/utils/checkstyle.py b/utils/checkstyle.py
index 335e58f5..41cd3371 100755
--- a/utils/checkstyle.py
+++ b/utils/checkstyle.py
@@ -102,7 +102,7 @@ class DiffHunkSide(object):
 
 
 class DiffHunk(object):
-    diff_header_regex = re.compile('@@ -([0-9]+),([0-9]+) \+([0-9]+),([0-9]+) @@')
+    diff_header_regex = re.compile(r'@@ -([0-9]+),([0-9]+) \+([0-9]+),([0-9]+) @@')
 
     def __init__(self, line):
         match = DiffHunk.diff_header_regex.match(line)