kselftest/arm64: tpidr2: Adjust to new clone() behaviour

kselftest/arm64: tpidr2: Adjust to new clone() behaviour

In order to fix an ABI problem, we recently changed the way that a
clone() syscall manipulates TPIDR2 and PSTATE.ZA. Historically the child
would inherit the parent's TPIDR2 value unless CLONE_SETTLS was set, and
now the child will inherit the parent's TPIDR2 value unless CLONE_VM is
set.

Update the tpidr2 test for the new behaviour.

Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Daniel Kiss <daniel.kiss@arm.com>
Cc: Marc Zyngier <maz@kernel.org>
Cc: Mark Brown <broonie@kernel.org>
Cc: Richard Sandiford <richard.sandiford@arm.com>
Cc: Sander De Smalen <sander.desmalen@arm.com>
Cc: Tamas Petz <tamas.petz@arm.com>
Cc: Will Deacon <will@kernel.org>
Cc: Yury Khrustalev <yury.khrustalev@arm.com>
Link: https://lore.kernel.org/r/20250508132644.1395904-23-mark.rutland@arm.com
Signed-off-by: Will Deacon <will@kernel.org>