target/loongarch: Fix return value of CHECK_FPE

target/loongarch: Fix return value of CHECK_FPE

Regarding the patchset v3 has been merged into main line, and not
approved, this patch updates to patchset v4.

Fixes: 2419978c ("target/loongarch: Fix emulation of float-point disable exception")
Link: https://lists.nongnu.org/archive/html/qemu-devel/2022-11/msg00808.html
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Signed-off-by: Rui Wang <wangrui@loongson.cn>
Message-Id: <20221107024526.702297-3-wangrui@loongson.cn>
Signed-off-by: Song Gao <gaosong@loongson.cn>