linux-user: Fix do_shmat type errors

The guest address, raddr, should be unsigned, aka abi_ulong.
The host addresses should be cast via *intptr_t not long.
Drop the inline and fix two other whitespace issues.

Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Reviewed-by: Anton Johansson <anjo@rev.ng>
Message-Id: <20230626140250.69572-1-richard.henderson@linaro.org>