cros_ec: Support reading EC features

The EC can support a variety of features and provides a way to find out
what is available. Add support for this.

Also update the feature list to the lastest available while we are here.
This is at:

   https://chromium.googlesource.com/chromiumos/platform/ec/+/refs/heads/master/include/ec_commands.h

Signed-off-by: Simon Glass <sjg@chromium.org>
diff --git a/drivers/misc/cros_ec_sandbox.c b/drivers/misc/cros_ec_sandbox.c
index 9324384..7213313 100644
--- a/drivers/misc/cros_ec_sandbox.c
+++ b/drivers/misc/cros_ec_sandbox.c
@@ -480,6 +480,17 @@
 		len = sizeof(*resp);
 		break;
 	}
+	case EC_CMD_GET_FEATURES: {
+		struct ec_response_get_features *resp = resp_data;
+
+		resp->flags[0] = EC_FEATURE_MASK_0(EC_FEATURE_FLASH) |
+			EC_FEATURE_MASK_0(EC_FEATURE_I2C);
+		resp->flags[1] =
+			EC_FEATURE_MASK_1(EC_FEATURE_UNIFIED_WAKE_MASKS) |
+			EC_FEATURE_MASK_1(EC_FEATURE_ISH);
+		len = sizeof(*resp);
+		break;
+	}
 	default:
 		printf("   ** Unknown EC command %#02x\n", req_hdr->command);
 		return -1;