[AArch64][SME] Enable TPIDR2 lazy-save for za_preserved

This change makes callees with the __arm_preserves_za
type attribute comply with the dormant state requirements
when it's caller has the __arm_shared_za type attribute.
Several external SME functions also do not need to lazy
save.

https://github.com/ARM-software/abi-aa/blob/5e67092434b50c04f8ad178a9c272ce3c6ada7fd/aapcs64/aapcs64.rst?plain=1#L1381

Differential Revision: https://reviews.llvm.org/D159186