boards: Raspberry Pi vendor fix

Use same vendor name for all R-Pi boards.

Signed-off-by: Erwan Gouriou <erwan.gouriou@st.com>

boards/xen/xenvm/Kconfig.defconfig

@@ -0,0 +1,9 @@
+# Copyright (c) 2020 EPAM Systems
+# SPDX-License-Identifier: Apache-2.0
+
+if BOARD_XENVM
+
+config BUILD_OUTPUT_BIN
+	default y
+
+endif # BOARD_XENVM