KVM: arm64: Initialize the kvm host data's fpsimd_state pointer in pKVM

KVM: arm64: Initialize the kvm host data's fpsimd_state pointer in pKVM

Since the host_fpsimd_state has been removed from kvm_vcpu_arch,
it isn't pointing to the hyp's version of the host fp_regs in
protected mode.

Initialize the host_data fpsimd_state point to the host_data's
context fp_regs on pKVM initialization.

Fixes: 51e09b5572d6 ("KVM: arm64: Exclude host_fpsimd_state pointer from kvm_vcpu_arch")
Signed-off-by: Fuad Tabba <tabba@google.com>
Acked-by: Oliver Upton <oliver.upton@linux.dev>
Link: https://lore.kernel.org/r/20240423150538.2103045-2-tabba@google.com
Signed-off-by: Marc Zyngier <maz@kernel.org>