cifsd: fix build warnings from cifsd.rst

Stephen reported a build warnings from cifsd.rst:

Documentation/filesystems/cifs/cifsd.rst:13: WARNING: Inline
substitution_reference start-string without end-string.
Documentation/filesystems/cifs/cifsd.rst:14: WARNING: Block quote ends
without a blank line; unexpected unindent.
Documentation/filesystems/cifs/cifsd.rst:14: WARNING: Inline
substitution_reference start-string without end-string.
Documentation/filesystems/cifs/cifsd.rst:18: WARNING: Block quote ends
without a blank line; unexpected unindent.
Documentation/filesystems/cifs/cifsd.rst:23: WARNING: Inline
substitution_reference start-string without end-string.
Documentation/filesystems/cifs/cifsd.rst:23: WARNING: Inline
substitution_reference start-string without end-string.
Documentation/filesystems/cifs/cifsd.rst:24: WARNING: Inline
substitution_reference start-string without end-string.
Documentation/filesystems/cifs/cifsd.rst:25: WARNING: Definition list
ends without a blank line; unexpected unindent.
Documentation/filesystems/cifs/cifsd.rst:28: WARNING: Unexpected
indentation.
Documentation/filesystems/cifs/cifsd.rst:31: WARNING: Block quote ends
without a blank line; unexpected unindent.
Documentation/filesystems/cifs/cifsd.rst:38: WARNING: Unexpected
indentation.
Documentation/filesystems/cifs/cifsd.rst:32: WARNING: Inline
substitution_reference start-string without end-string.
Documentation/filesystems/cifs/cifsd.rst:32: WARNING: Inline
substitution_reference start-string without end-string.
Documentation/filesystems/cifs/cifsd.rst:39: WARNING: Block quote ends
without a blank line; unexpected unindent.
Documentation/filesystems/cifs/cifsd.rst:14: WARNING: Undefined
substitution referenced: "--- ksmbd/3 - Client 3 |-------".
Documentation/filesystems/cifs/cifsd.rst:0: WARNING: Undefined
substitution referenced:
"____________________________________________________".
Documentation/filesystems/cifs/cifsd.rst:25: WARNING: Undefined
substitution referenced: "--- ksmbd/0(forker kthread) ---------------|".
Documentation/filesystems/cifs/cifsd.rst:32: WARNING: Undefined
substitution referenced:
"______________________________________________".

Signed-off-by: Namjae Jeon <namjae.jeon@samsung.com>
Signed-off-by: Steve French <stfrench@microsoft.com>