buildman: Drop use of 'board' in board module

Use brds instead so that we can reserve 'boards' and 'board' as module
names.

Signed-off-by: Simon Glass <sjg@chromium.org>
diff --git a/tools/buildman/board.py b/tools/buildman/board.py
index 08771b3..8de71e4 100644
--- a/tools/buildman/board.py
+++ b/tools/buildman/board.py
@@ -116,7 +116,7 @@
     def ReadBoards(self, fname):
         """Read a list of boards from a board file.
 
-        Create a board object for each and add it to our _boards list.
+        Create a Board object for each and add it to our _boards list.
 
         Args:
             fname: Filename of boards.cfg file
@@ -238,21 +238,21 @@
             terms.append(term)
         return terms
 
-    def SelectBoards(self, args, exclude=[], boards=None):
+    def SelectBoards(self, args, exclude=[], brds=None):
         """Mark boards selected based on args
 
         Normally either boards (an explicit list of boards) or args (a list of
         terms to match against) is used. It is possible to specify both, in
         which case they are additive.
 
-        If boards and args are both empty, all boards are selected.
+        If brds and args are both empty, all boards are selected.
 
         Args:
             args: List of strings specifying boards to include, either named,
                   or by their target, architecture, cpu, vendor or soc. If
                   empty, all boards are selected.
             exclude: List of boards to exclude, regardless of 'args'
-            boards: List of boards to build
+            brds: List of boards to build
 
         Returns:
             Tuple
@@ -283,8 +283,8 @@
                         matching_term = str(term)
                         build_it = True
                         break
-            elif boards:
-                if brd.target in boards:
+            elif brds:
+                if brd.target in brds:
                     build_it = True
                     found.append(brd.target)
             else:
@@ -302,8 +302,8 @@
                     result[matching_term].append(brd.target)
                 result['all'].append(brd.target)
 
-        if boards:
-            remaining = set(boards) - set(found)
+        if brds:
+            remaining = set(brds) - set(found)
             if remaining:
                 warnings.append('Boards not found: %s\n' % ', '.join(remaining))