target/mips: Fix msa checking condition in trans_msa_elm_fn()

target/mips: Fix msa checking condition in trans_msa_elm_fn()

Fix issue that condition of check_msa_enabled(ctx) is reversed
that causes segfault when msa elm_fn op encountered.

Fixes: 2f2745c81a ("target/mips: Convert MSA COPY_U opcode to decodetree")
Fixes: 97fe675519 ("target/mips: Convert MSA COPY_S and INSERT opcodes to decodetree")
Signed-off-by: Ni Hui <shuizhuyuanluo@126.com>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Message-Id: <20220503130708.272850-3-shuizhuyuanluo@126.com>
Signed-off-by: Philippe Mathieu-Daudé <f4bug@amsat.org>