KVM: arm64: Remove redundant hyp_assert_lock_held() assertions

host_stage2_try() asserts that the KVM host lock is held, so there's no
need to duplicate the assertion in its wrappers.

Signed-off-by: Will Deacon <will@kernel.org>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20220609121223.2551-6-will@kernel.org