BB: vgv7519: support more recent board release with vrx288 v1.2

The existance of this new board has been confirmed and tested by the guy on this commit

https://github.com/openwrt-vgv7519/uboot-bin/commit/76fdd8e638f81e324ffe77856481bd147398f6e8

git-svn-id: svn://svn.openwrt.org/openwrt/branches/barrier_breaker@43075 3c298f89-4303-0410-b956-a3cf2f4a3e73