KVM: arm64: Use kvm_has_mte() in pKVM trap initialization

KVM: arm64: Use kvm_has_mte() in pKVM trap initialization

When initializing HCR traps in protected mode, use kvm_has_mte() to
check for MTE support rather than kvm_has_feat(kvm, ID_AA64PFR1_EL1,
MTE, IMP).

kvm_has_mte() provides a more comprehensive check:
 - kvm_has_feat() only checks if MTE is in the guest's ID register view
   (i.e., what we advertise to the guest)
 - kvm_has_mte() checks both system_supports_mte() AND whether
   KVM_ARCH_FLAG_MTE_ENABLED is set for this VM instance

Signed-off-by: Fuad Tabba <tabba@google.com>
Link: https://patch.msgid.link/20260122112218.531948-5-tabba@google.com
Signed-off-by: Marc Zyngier <maz@kernel.org>