external/gard: add Makefile targets to make debian packages
external/gard: add Makefile targets to make debian packages

The Makefile is missing a install target which will be needed to package and
distribute into ubuntu.

Added a simple install target.

Signed-off-by: Cyril Bur <6ce38dade8c4b52fd55c193fae70fd1d1275c3c3@au1.ibm.com>
Signed-off-by: Stewart Smith <ec31ab75ddf977353c8f660f92ea8b23f64aef25@linux.vnet.ibm.com>

shenki/skiboot,ddstreet/skiboot,qemu/skiboot,open-power/skiboot,ddstreet/skiboot,legoater/skiboot,stewart-ibm/skiboot,qemu/skiboot,mikey/skiboot,csmart/skiboot,mikey/skiboot,qemu/skiboot,ddstreet/skiboot,apopple/skiboot,shenki/skiboot,open-power/skiboot,shenki/skiboot,qemu/skiboot,csmart/skiboot,open-power/skiboot,legoater/skiboot,open-power/skiboot,apopple/skiboot,qemu/skiboot,legoater/skiboot,shenki/skiboot,stewart-ibm/skiboot,stewart-ibm/skiboot,apopple/skiboot,legoater/skiboot,legoater/skiboot,shenki/skiboot,open-power/skiboot,csmart/skiboot,mikey/skiboot