The conversion of rndis friendly name to utf8 uses a standard
kernel routine which is optional in config. Therefore build
would fail for some configurations. Resolve by selecting needed
library.
Fixes: 0fe554a46a0f ("hv_netvsc: propogate Hyper-V friendly name into interface alias")
Signed-off-by: Stephen Hemminger <sthemmin@microsoft.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
 config HYPERV_NET
        tristate "Microsoft Hyper-V virtual network driver"
        depends on HYPERV
+       select UCS2_STRING
        help
          Select this option to enable the Hyper-V virtual network driver.