MIPS: Enable some missed configs in loongson3_defconfig to support bpftrace

MIPS: Enable some missed configs in loongson3_defconfig to support bpftrace

bpftrace is a high-level tracing language for Linux enhanced Berkeley
Packet Filter (eBPF) available in recent Linux kernels (4.x). bpftrace
uses LLVM as a backend to compile scripts to BPF-bytecode and makes use
of BCC for interacting with the Linux BPF system, as well as existing
Linux tracing capabilities: kernel dynamic tracing (kprobes), user-level
dynamic tracing (uprobes), and tracepoints.

According to Linux Kernel Requirements in bpftrace/INSTALL.md [1], the
kernel needs to be built with the following options:

CONFIG_BPF=y
CONFIG_BPF_SYSCALL=y
CONFIG_BPF_JIT=y
CONFIG_HAVE_EBPF_JIT=y
CONFIG_BPF_EVENTS=y
CONFIG_FTRACE_SYSCALLS=y
CONFIG_FUNCTION_TRACER=y
CONFIG_HAVE_DYNAMIC_FTRACE=y
CONFIG_DYNAMIC_FTRACE=y
CONFIG_HAVE_KPROBES=y
CONFIG_KPROBES=y
CONFIG_KPROBE_EVENTS=y
CONFIG_ARCH_SUPPORTS_UPROBES=y
CONFIG_UPROBES=y
CONFIG_UPROBE_EVENTS=y
CONFIG_DEBUG_FS=y

So enable some missed configs in loongson3_defconfig to make sure
the above configs are set after make loongson3_defconfig.

[1] https://github.com/iovisor/bpftrace/blob/master/INSTALL.md

Signed-off-by: Tiezhu Yang <yangtiezhu@loongson.cn>
Signed-off-by: Thomas Bogendoerfer <tsbogend@alpha.franken.de>