KVM: x86: Drop guest-triggerable ASSERT()s on I/O APIC access alignment

KVM: x86: Drop guest-triggerable ASSERT()s on I/O APIC access alignment

Drop the asserts on the guest-controlled address being 16-byte aligned
when emulating I/O APIC accesses, as the ASSERT()s are guest-triggerable
and ultimately pointless since KVM requires exact register matches, i.e.
will ultimately ignore unaligned accesses anyways.

Drop the ASSERT() definition itself now that all users are gone.

For all intents and purposes, no functional change intended.

Link: https://patch.msgid.link/20251206004311.479939-5-seanjc@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>