LoongArch: BPF: Set bpf_jit_bypass_spec_v1/v4()

JITs can set bpf_jit_bypass_spec_v1/v4() if they want the verifier to
skip analysis/patching for the respective vulnerability, it is safe to
set both bpf_jit_bypass_spec_v1/v4(), because there is no speculation
barrier instruction for LoongArch.

Suggested-by: Luis Gerhorst <luis.gerhorst@fau.de>
Signed-off-by: Tiezhu Yang <yangtiezhu@loongson.cn>
Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>