platform/chrome: cros_ec_proto: remove big stub objects from stack

sizeof(struct device) = 680
sizeof(struct cros_ec_dev) = 720

They tend to exceed the stack frame size limit in some specific
environment which results in the following compilation error:

>> drivers/platform/chrome/cros_ec_proto_test.c:2530:13: error: stack
frame size (2128) exceeds limit (2048) in
'cros_ec_proto_test_get_sensor_count_legacy'

Remove the big stub objects from stack.

This is:
$ sed -i 's/struct cros_ec_dev /static struct cros_ec_dev /' \
    drivers/platform/chrome/cros_ec_proto_test.c

Reported-by: kernel test robot <lkp@intel.com>
Signed-off-by: Tzung-Bi Shih <tzungbi@kernel.org>
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Link: https://lore.kernel.org/r/20230117080254.2725536-1-tzungbi@kernel.org

Author: Tzung-Bi Shih

drivers/platform/chrome/cros_ec_proto_test.c

@@ -2371,7 +2371,7 @@ static void cros_ec_proto_test_get_host_event_normal(struct kunit *test)
 static void cros_ec_proto_test_check_features_cached(struct kunit *test)
 {
 	int ret, i;
-	struct cros_ec_dev ec;
+	static struct cros_ec_dev ec;
 
 	ec.features.flags[0] = EC_FEATURE_MASK_0(EC_FEATURE_FINGERPRINT);
 	ec.features.flags[1] = EC_FEATURE_MASK_0(EC_FEATURE_SCP);
@@ -2396,7 +2396,7 @@ static void cros_ec_proto_test_check_features_not_cached(struct kunit *test)
 	struct cros_ec_device *ec_dev = &priv->ec_dev;
 	struct ec_xfer_mock *mock;
 	int ret, i;
-	struct cros_ec_dev ec;
+	static struct cros_ec_dev ec;
 
 	ec_dev->max_request = 0xff;
 	ec_dev->max_response = 0xee;
@@ -2449,7 +2449,7 @@ static void cros_ec_proto_test_get_sensor_count_normal(struct kunit *test)
 	struct cros_ec_device *ec_dev = &priv->ec_dev;
 	struct ec_xfer_mock *mock;
 	int ret;
-	struct cros_ec_dev ec;
+	static struct cros_ec_dev ec;
 
 	ec_dev->max_request = 0xff;
 	ec_dev->max_response = 0xee;
@@ -2494,7 +2494,7 @@ static void cros_ec_proto_test_get_sensor_count_xfer_error(struct kunit *test)
 	struct cros_ec_device *ec_dev = &priv->ec_dev;
 	struct ec_xfer_mock *mock;
 	int ret;
-	struct cros_ec_dev ec;
+	static struct cros_ec_dev ec;
 
 	ec_dev->max_request = 0xff;
 	ec_dev->max_response = 0xee;
@@ -2534,7 +2534,7 @@ static void cros_ec_proto_test_get_sensor_count_legacy(struct kunit *test)
 	struct cros_ec_device *ec_dev = &priv->ec_dev;
 	struct ec_xfer_mock *mock;
 	int ret, i;
-	struct cros_ec_dev ec;
+	static struct cros_ec_dev ec;
 	struct {
 		u8 readmem_data;
 		int expected_result;