docs: virt/kvm: close inline string literal

This fixes

	Documentation/virt/kvm/amd-memory-encryption.rst:76: WARNING: Inline literal start-string without end-string.

Fixes: 2da1ed62 ("KVM: SVM: document KVM_MEM_ENCRYPT_OP, let userspace detect if SEV is available")
Signed-off-by: Stephen Kitt <steve@sk2.org>
Link: https://lore.kernel.org/r/20200424152637.120876-1-steve@sk2.orgSigned-off-by: Jonathan Corbet <corbet@lwn.net>

Documentation/virt/kvm/amd-memory-encryption.rst

@@ -74,7 +74,7 @@ should point to a file descriptor that is opened on the ``/dev/sev``
 device, if needed (see individual commands).
 
 On output, ``error`` is zero on success, or an error code.  Error codes
-are defined in ``<linux/psp-dev.h>`.
+are defined in ``<linux/psp-dev.h>``.
 
 KVM implements the following commands to support common lifecycle events of SEV
 guests, such as launching, running, snapshotting, migrating and decommissioning.