linux-user: Fix handling of arm_fadvise64_64 syscall

linux-user: Fix handling of arm_fadvise64_64 syscall

32-bit ARM has an odd variant of the fadvise syscall which has
rearranged arguments, which we try to implement. Unfortunately we got
the rearrangement wrong.

This is a six-argument syscall whose arguments are:
 * fd
 * advise parameter
 * offset high half
 * offset low half
 * len high half
 * len low half

Stop trying to share code with the standard fadvise syscalls,
and just implement the syscall with the correct argument order.

Signed-off-by: Peter Maydell <[email protected]>
Reviewed-by: Laurent Vivier <[email protected]>
Signed-off-by: Riku Voipio <[email protected]>