ANDROID: x86: disable STACK_VALIDATION with LTO_CLANG

Disable CONFIG_STACK_VALIDATION with LTO, because objtool doesn't
understand LLVM IR.

Bug: 133186739
Bug: 145297900
Change-Id: I3f2bd3f0ce6c80f88bd00394453b543f884188f2
Signed-off-by: Sami Tolvanen <samitolvanen@google.com>