ubsan: Avoid i386 UBSAN handler crashes with Clang

ubsan: Avoid i386 UBSAN handler crashes with Clang

When generating Runtime Calls, Clang doesn't respect the -mregparm=3
option used on i386. Hopefully this will be fixed correctly in Clang 19:
https://github.com/llvm/llvm-project/pull/89707
but we need to fix this for earlier Clang versions today. Force the
calling convention to use non-register arguments.

Reported-by: Erhard Furtner <erhard_f@mailbox.org>
Closes: https://github.com/KSPP/linux/issues/350
Link: https://lore.kernel.org/r/20240424224026.it.216-kees@kernel.org
Acked-by: Nathan Chancellor <nathan@kernel.org>
Acked-by: Justin Stitt <justinstitt@google.com>
Signed-off-by: Kees Cook <keescook@chromium.org>