rust: fix bindgen build error with UBSAN_BOUNDS_STRICT

With commit 2d47c69 ("ubsan: Tighten UBSAN_BOUNDS on GCC") if
CONFIG_UBSAN is enabled and gcc supports -fsanitize=bounds-strict, we
can trigger the following build error due to bindgen lacking support for
this additional build option:

   BINDGEN rust/bindings/bindings_generated.rs
 error: unsupported argument 'bounds-strict' to option '-fsanitize='

Fix by adding -fsanitize=bounds-strict to the list of skipped gcc flags
for bindgen.

Fixes: 2d47c69 ("ubsan: Tighten UBSAN_BOUNDS on GCC")
Signed-off-by: Andrea Righi <andrea.righi@canonical.com>
Acked-by: Kees Cook <keescook@chromium.org>
Reviewed-by: Martin Rodriguez Reboredo <yakoyoku@gmail.com>
Link: https://lore.kernel.org/r/20230711071914.133946-1-andrea.righi@canonical.com
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>

Author: Andrea Righi

rust/Makefile

@@ -257,7 +257,7 @@ bindgen_skip_c_flags := -mno-fp-ret-in-387 -mpreferred-stack-boundary=% \
 	-fno-partial-inlining -fplugin-arg-arm_ssp_per_task_plugin-% \
 	-fno-reorder-blocks -fno-allow-store-data-races -fasan-shadow-offset=% \
 	-fzero-call-used-regs=% -fno-stack-clash-protection \
-	-fno-inline-functions-called-once \
+	-fno-inline-functions-called-once -fsanitize=bounds-strict \
 	--param=% --param asan-%
 
 # Derived from `scripts/Makefile.clang`.