juno: Optimization level changed for Juno build

The transport layer based fast channel implementation is causing
Juno ramfw to be oversized which is causing boot failure.

This patch changes the optimization level of Juno build from default
Og to O2 to reduce the code size.

Signed-off-by: Md Golam Tanvir Zim <mdgolamtanvir.zim@arm.com>
Change-Id: I30bb32e49cb3dd8518b8eb8781c4892ca0fbb911
1 file changed