target/rx: Use prt_ldmi for XCHG_mr disassembly

target/rx: Use prt_ldmi for XCHG_mr disassembly

Note that the ld == 3 case handled by prt_ldmi is decoded as
XCHG_rr and cannot appear here.

Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Reviewed-by: Yoshinori Sato <ysato@users.sourceforge.jp>
Tested-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Message-Id: <20190531134315.4109-21-richard.henderson@linaro.org>
Acked-by: Richard Henderson <richard.henderson@linaro.org>
Signed-off-by: Philippe Mathieu-Daudé <f4bug@amsat.org>