test/py: fix CONFIG_SPL test

The Python ini file parser that's used to parse .config converts all keys
to lower-case. Hence, all queries against the results must use lower-case.
Fix u_boot_console.ensure_spawned() to test CONFIG_SPL correctly, or the
connection will fail for boards that have SPL.

Signed-off-by: Stephen Warren <swarren@nvidia.com>
Acked-by: Simon Glass <sjg@chromium.org>

test/py/u_boot_console_base.py

@@ -303,7 +303,7 @@ class ConsoleBase(object):
             if not self.config.gdbserver:
                 self.p.timeout = 30000
             self.p.logfile_read = self.logstream
-            if self.config.buildconfig.get('CONFIG_SPL', False) == 'y':
+            if self.config.buildconfig.get('config_spl', False) == 'y':
                 m = self.p.expect([pattern_u_boot_spl_signon] + self.bad_patterns)
                 if m != 0:
                     raise Exception('Bad pattern found on console: ' +