spec: Silence benign warnings in 3rd party code

Do not warn about excessive shifts in imported Xilinx driver code when
building with the ILP32 ABI. The two instances of this warning produce
the desired effect of setting the upper address bits to 0.

spec/build/bsps/objnandpsu.yml

@@ -1,6 +1,7 @@
 SPDX-License-Identifier: CC-BY-SA-4.0 OR BSD-2-Clause
 build-type: objects
-cflags: []
+cflags:
+- -Wno-shift-count-overflow
 copyrights:
 - Copyright (C) 2022 On-Line Applications Research (OAR)
 cppflags: []

spec/build/bsps/objqspipsu.yml

@@ -1,6 +1,7 @@
 SPDX-License-Identifier: CC-BY-SA-4.0 OR BSD-2-Clause
 build-type: objects
-cflags: []
+cflags:
+- -Wno-shift-count-overflow
 copyrights:
 - Copyright (C) 2022 On-Line Applications Research (OAR)
 cppflags: []