KVM: arm64: Fix FEAT_SPE_FnE to use PMSIDR_EL1.FnE, not PMSVer

KVM: arm64: Fix FEAT_SPE_FnE to use PMSIDR_EL1.FnE, not PMSVer

FEAT_SPE_FnE is architecturally detected via PMSIDR_EL1.FnE [6], not
ID_AA64DFR0_EL1.PMSVer. The FEAT_X macro form (register, field, value)
cannot encode a PMSIDR_EL1-based feature, so FEAT_SPE_FnE was defined
identically to FEAT_SPEv1p2 (ID_AA64DFR0_EL1, PMSVer, V1P2), producing
a duplicate that used PMSVer >= V1P2 as a proxy.

Replace the macro with feat_spe_fne(), following the same pattern as
the sibling feat_spe_fds(): guard on FEAT_SPEv1p2 and read
PMSIDR_EL1.FnE [6] directly. Wire the two NEEDS_FEAT consumers to use
the new function.

Remove the now-unused FEAT_SPE_FnE macro.

Fixes: 63d423a7635b ("KVM: arm64: Switch to table-driven FGU configuration")
Signed-off-by: Fuad Tabba <tabba@google.com>
Link: https://patch.msgid.link/20260424084908.370776-4-tabba@google.com
Signed-off-by: Marc Zyngier <maz@kernel.org>
Cc: stable@vger.kernel.org