add .gitignore
cores: add altera_virtual_jtag core

Used as a wrapper to altera virtual jtag by advanced debug sys,
but isn't limited to that.
de0_nano: use common altera_virtual_jtag core
Merge branch 'for-openrisc' of https://github.com/skristiansson/orpsoc-cores
cores: mt48lc16m16a2: fix variable case in patch 0004

Signed-off-by: Franck Jullien <franck.jullien@gmail.com>