The GCC Optimization Levels AGAIN [1/2]

So after lurking around, I found out that we didn't set up the GCC Optimization
Levels to the TARGET_linux_mips.mk and I also found out that the Global Cflags
for TARGET_linux-x86.mk uses O2 in by default. Now I added those GCC
Optimization Levels to it but I'm not sure if they work? ¯\_(ツ)_/¯

PS2: Tabs.
PS3: Update the commit message..
PS4: DONE UPDATING THE COMMIT MESSAGE!

Change-Id: Ibd9e0b5580bdd4d9a865741d856486c35ca1f7f6
Signed-off-by: Lokesh Chamane <lokesh.c703@gmail.com>