target/mips: Have gen_[d]lsa() callers add 1 to shift amount argument

target/mips: Have gen_[d]lsa() callers add 1 to shift amount argument

Having the callee add 1 to shift amount is misleading (see the
NM_LSA case in decode_nanomips_32_48_opc() where we have to
manually substract 1). Rather have the callers pass a modified
$sa.

Suggested-by: Richard Henderson <richard.henderson@linaro.org>
Signed-off-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Message-Id: <20241112172022.88348-4-philmd@linaro.org>