LoongArch: Use larch_insn_gen_break() for kprobes

mainline inclusion
from mainline-v6.5-rc1
commit 6e320363
category: bugfix
bugzilla: https://gitee.com/openeuler/kernel/issues/I7MWTU


CVE: NA

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For now, we can use larch_insn_gen_break() to define KPROBE_BP_INSN and
KPROBE_SSTEPBP_INSN. Because larch_insn_gen_break() returns instruction
word, define kprobe_opcode_t as u32, then do some small changes related
with type conversion, no functional change intended.

Signed-off-by: Yongzhen Zhang <zhangyongzhen@kylinos.cn>
Tested-by: Jeff Xie <xiehuan09@gmail.com>
Signed-off-by: Tiezhu Yang <yangtiezhu@loongson.cn>
Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>