use SLOB allocator for embedded systems

target/linux/kernel.config

@@ -7,6 +7,7 @@ CONFIG_SYSVIPC=y
 CONFIG_SYSVIPC_SYSCTL=y
 CONFIG_POSIX_MQUEUE=y
 CONFIG_POSIX_MQUEUE_SYSCTL=y
+CONFIG_SLOB=y
 CONFIG_NET=y
 CONFIG_PACKET=y
 CONFIG_UNIX=y