test: Create a common function to get the config

The settings are decoded in two places. Combine them into a new
function, before (in a future patch) expanding the number of items.

Signed-off-by: Simon Glass <sjg@chromium.org>
diff --git a/test/py/conftest.py b/test/py/conftest.py
index fc9dd3a..85e1979 100644
--- a/test/py/conftest.py
+++ b/test/py/conftest.py
@@ -115,14 +115,36 @@
         runner.close()
         log.status_pass('OK')
 
-def pytest_xdist_setupnodes(config, specs):
-    """Clear out any 'done' file from a previous build"""
-    global build_done_file
-    build_dir = config.getoption('build_dir')
+def get_details(config):
+    """Obtain salient details about the board and directories to use
+
+    Args:
+        config (pytest.Config): pytest configuration
+
+    Returns:
+        tuple:
+            str: Board type (U-Boot build name)
+            str: Identity for the lab board
+            str: Build directory
+            str: Source directory
+    """
     board_type = config.getoption('board_type')
+    board_identity = config.getoption('board_identity')
+    build_dir = config.getoption('build_dir')
+
     source_dir = os.path.dirname(os.path.dirname(TEST_PY_DIR))
+    default_build_dir = source_dir + '/build-' + board_type
     if not build_dir:
-        build_dir = source_dir + '/build-' + board_type
+        build_dir = default_build_dir
+
+    return board_type, board_identity, build_dir, source_dir
+
+def pytest_xdist_setupnodes(config, specs):
+    """Clear out any 'done' file from a previous build"""
+    global build_done_file
+
+    build_dir = get_details(config)[2]
+
     build_done_file = Path(build_dir) / 'build.done'
     if build_done_file.exists():
         os.remove(build_done_file)
@@ -161,17 +183,10 @@
     global console
     global ubconfig
 
-    source_dir = os.path.dirname(os.path.dirname(TEST_PY_DIR))
+    board_type, board_identity, build_dir, source_dir = get_details(config)
 
-    board_type = config.getoption('board_type')
     board_type_filename = board_type.replace('-', '_')
-
-    board_identity = config.getoption('board_identity')
     board_identity_filename = board_identity.replace('-', '_')
-
-    build_dir = config.getoption('build_dir')
-    if not build_dir:
-        build_dir = source_dir + '/build-' + board_type
     mkdir_p(build_dir)
 
     result_dir = config.getoption('result_dir')