tipc: Remove redundant call to TLV_SPACE()

The purpose of TLV_SPACE() is to add the TLV descriptor size to the size of
the TLV value passed as argument and align the resulting size to
TLV_ALIGNTO.

tipc_tlv_alloc() calls TLV_SPACE() on its argument. In other words,
tipc_tlv_alloc() takes its argument as the size of the TLV value. So the
call to TLV_SPACE() in tipc_get_err_tlv() is redundant. Let's remove this
redundancy.

Acked-by: Paolo Abeni <pabeni@redhat.com>
Signed-off-by: Shigeru Yoshida <syoshida@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>