arm64/signal: Alloc tpidr2 sigframe after checking system_supports_tpidr2()

Move tpidr2 sigframe allocation from under the checking of
system_supports_sme() to the checking of system_supports_tpidr2().

Signed-off-by: Dongxu Sun <sundongxu3@huawei.com>
Reviewed-by: Mark Brown <broonie@kernel.org>
Link: https://lore.kernel.org/r/20230317124915.1263-3-sundongxu3@huawei.com


Signed-off-by: Will Deacon <will@kernel.org>