KVM: arm64: Remove trailing whitespace in comment

Remove trailing whitespace from comment in trap_dbgauthstatus_el1().

No functional change intended.
Acked-by: Will Deacon <will@kernel.org>
Signed-off-by: Fuad Tabba <tabba@google.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20210817081134.2918285-3-tabba@google.com