target/i386: Do not apply REX to MMX operands

target/i386: Do not apply REX to MMX operands

Cc: qemu-stable@nongnu.org
Fixes: b3e22b2318a ("target/i386: add core of new i386 decoder")
Resolves: https://gitlab.com/qemu-project/qemu/-/issues/2495
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Link: https://lore.kernel.org/r/20240812025844.58956-2-richard.henderson@linaro.org
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
(cherry picked from commit 416f2b16c02c618c0f233372ebfe343f9ee667d4)
Signed-off-by: Michael Tokarev <mjt@tls.msk.ru>