Revert "cifs: In Kconfig CONFIG_CIFS_POSIX needs depends on legacy (insecure cifs)"

BugLink: https://bugs.launchpad.net/bugs/1818813

This reverts commit 60da90b2 which is
commit 6e785302 upstream.

Yi writes:
	I notice that 4.4.169 merged 60da90b2 ("cifs: In Kconfig
	CONFIG_CIFS_POSIX needs depends on legacy (insecure cifs)") add
	a Kconfig dependency CIFS_ALLOW_INSECURE_LEGACY, which was not
	defined in 4.4 stable, so after this patch we are not able to
	enable CIFS_POSIX anymore. Linux 4.4 stable didn't merge the
	legacy dialects codes, so do we really need this patch for 4.4?

So revert this patch.
Reported-by: "zhangyi (F)" <yi.zhang@huawei.com>
Cc: Steve French <stfrench@microsoft.com>
Cc: Pavel Shilovsky <pshilov@microsoft.com>
Cc: Sasha Levin <sashal@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Juerg Haefliger <juergh@canonical.com>
Signed-off-by: Khalid Elmously <khalid.elmously@canonical.com>

fs/cifs/Kconfig

@@ -109,7 +109,7 @@ config CIFS_XATTR
 
 config CIFS_POSIX
         bool "CIFS POSIX Extensions"
-        depends on CIFS && CIFS_ALLOW_INSECURE_LEGACY && CIFS_XATTR
+        depends on CIFS_XATTR
         help
           Enabling this option will cause the cifs client to attempt to
 	  negotiate a newer dialect with servers, such as Samba 3.0.5