linux-user: Fix structure target_semid64_ds definition for Mips

linux-user: Fix structure target_semid64_ds definition for Mips

This patch corrects target_semid64_ds structure definition for Mips.

See, for example definition of semid64_ds for Mips in Linux kernel:
arch/mips/include/uapi/asm/sembuf.h#L13.

This patch will also fix certain semaphore-related LTP tests for Mips,
if they are executed in Qemu user mode for any Mips platform.

Signed-off-by: Miodrag Dinic <miodrag.dinic@imgtec.com>
Signed-off-by: Aleksandar Markovic <aleksandar.markovic@imgtec.com>
Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Laurent Vivier <laurent@vivier.eu>
Reviewed-by: Leon Alrae <leon.alrae@imgtec.com>
Acked-by: Riku Voipio <riku.voipio@linaro.org>
Signed-off-by: Leon Alrae <leon.alrae@imgtec.com>