linux-user: Use 'last' instead of 'end' in target_mmap

Complete the transition within the mmap functions to a formulation
that does not overflow at the end of the address space.

Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Message-Id: <20230707204054.8792-20-richard.henderson@linaro.org>
1 file changed