[AArch64] Force streaming-compatible codegen when attributes are set.

Before this patch, the only way to generate streaming-compatible code
was to use the `-force-streaming-compatible-sve` flag, but the compiler
should also avoid the use of instructions invalid in streaming mode
when a function has the aarch64_pstate_sm_enabled/compatible attribute.

Reviewed By: paulwalker-arm, david-arm

Differential Revision: https://reviews.llvm.org/D155428