Fix undefined reference error

If the yaml file doesn't contain one of BMC/ETHERNET/ETHERNET1
description, build fails with undefined reference error.
For instance, missed ETHERNET1:
write.cpp:54: undefined reference to
`void openpower::vpd::inventory::writeFru<(openpower::vpd::Fru)2>

The patch adds default implementation for function writeFru().

Resolves
https://github.com/openbmc/openpower-vpd-parser/issues/1

Signed-off-by: Artem Senichev <a.senichev@yadro.com>
Change-Id: Ibf6c649ca504c2c0e9e3a0d8fefd54375777193d
1 file changed