bluedroid: Fix build with gcc 4.8+

Use -Wno-error=unused-parameter with gcc >= 4.8

Change-Id: I330a56b0363b90118628bc3b30451f8921ca6f60
Signed-off-by: Bernhard Rosenkränzer <Bernhard.Rosenkranzer@linaro.org>
bluedroid: Fix build with gcc 4.8+

Use -Wno-error=unused-parameter with gcc >= 4.8

Change-Id: Id7299c8f0a1e2dd683647d49225342ebfa0a8dcf