powerpc: compile kernel for linkstations optimized for size

Since Linkstations and Kuroboxes often have *very* little memory (as
they are embedded systems), it is desirable to get their kernels
compiled optimized for size.
Signed-off-by: Rogério Brito <rbrito@ime.usp.br>
Signed-off-by: Kumar Gala <galak@kernel.crashing.org>

arch/powerpc/configs/linkstation_defconfig

@@ -90,7 +90,7 @@ CONFIG_NAMESPACES=y
 # CONFIG_PID_NS is not set
 CONFIG_BLK_DEV_INITRD=y
 CONFIG_INITRAMFS_SOURCE=""
-# CONFIG_CC_OPTIMIZE_FOR_SIZE is not set
+CONFIG_CC_OPTIMIZE_FOR_SIZE=y
 CONFIG_SYSCTL=y
 # CONFIG_EMBEDDED is not set
 CONFIG_SYSCTL_SYSCALL=y