arm64/ptrace: Use system_supports_tpidr2() to check for TPIDR2 support

arm64/ptrace: Use system_supports_tpidr2() to check for TPIDR2 support

We have a separate system_supports_tpidr2() to check for TPIDR2 support
but were using system_supports_sme() in tls_set(). While these are
currently identical let's use the specific check instead so we don't have
any surprises in future.

Reported-by: Will Deacon <will@kernel.org>
Signed-off-by: Mark Brown <broonie@kernel.org>
Link: https://lore.kernel.org/r/20221208-arm64-tpidr2-ptrace-feat-v2-1-3760c895a574@kernel.org
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>