target/loongarch: Support QMP dump-guest-memory

target/loongarch: Support QMP dump-guest-memory

Add the support needed for creating prstatus elf notes. This allows
us to use QMP dump-guest-memory.

Now ELF notes of LoongArch only supports general elf notes, LSX and
LASX is not supported, since it is mainly used to dump guest memory.

Signed-off-by: Bibo Mao <maobibo@loongson.cn>
Reviewed-by: Song Gao <gaosong@loongson.cn>
Tested-by: Song Gao <gaosong@loongson.cn>
Message-Id: <20240822065245.2286214-1-maobibo@loongson.cn>
Signed-off-by: Song Gao <gaosong@loongson.cn>