Extract gen_lsa() from translate.c and explode it as
gen_LSA() and gen_DLSA().

Signed-off-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Message-Id: <20201215225757.764263-22-f4bug@amsat.org>