cifs: Change translation of STATUS_PRIVILEGE_NOT_HELD to -EPERM

STATUS_PRIVILEGE_NOT_HELD indicates that user does not have privilege to
issue some operation, for example to create symlink.

Currently STATUS_PRIVILEGE_NOT_HELD is translated to -EIO. Change it to
-EPERM which better describe this error code.

Note that there is no ERR* code usable in ntstatus_to_dos_map[] table which
can be used to -EPERM translation, so do explicit translation in
map_smb_to_linux_error() function.

Signed-off-by: Pali Rohár <pali@kernel.org>
Acked-by: Tom Talpey <tom@talpey.com>
Acked-by: Paulo Alcantara (Red Hat) <pc@manguebit.com>
Signed-off-by: Steve French <stfrench@microsoft.com>