target/i386: fix x86_64 pushw op

target/i386: fix x86_64 pushw op

For x86_64 a 16 bit push op (pushw) of a memory address would generate
a 64 bit store on the stack instead of a 16 bit store.

For example:
        pushw (%rax)

behaves like
        pushq (%rax)

which is incorrect.

This patch fixes that.

Signed-off-by: Thomas Ogrisegg <tom-bugs-qemu@fnord.at>
Link: https://lore.kernel.org/r/20250715210307.GA1115@x1.fnord.at
Cc: qemu-stable@nongnu.org
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
(cherry picked from commit 5a2faa0a0a2cbdad4a108a0e122b0e51b9bc94fd)
Signed-off-by: Michael Tokarev <mjt@tls.msk.ru>