ksmbd: fix buffer validation by including null terminator size in EA length

ksmbd: fix buffer validation by including null terminator size in EA length

The smb2_set_ea function, which handles Extended Attributes (EA),
was performing buffer validation checks that incorrectly omitted the size
of the null terminating character (+1 byte) for EA Name.
This patch fixes the issue by explicitly adding '+ 1' to EaNameLength where
the null terminator is expected to be present in the buffer, ensuring
the validation accurately reflects the total required buffer size.

Cc: stable@vger.kernel.org
Reported-by: Roger <roger.andersen@protonmail.com>
Reported-by: Stanislas Polu <spolu@dust.tt>
Signed-off-by: Namjae Jeon <linkinjeon@kernel.org>
Signed-off-by: Steve French <stfrench@microsoft.com>