linux-user, openrisc: sync syscall numbers with kernel v5.5

linux-user, openrisc: sync syscall numbers with kernel v5.5

Use helper script scripts/gensyscalls.sh to generate the file.

Add TARGET_NR_or1k_atomic
Remove useless comments and blank lines.
Define diretly the __NR_XXX64 syscalls rather than using the
intermediate __NR3264 definition.

Remove wrong cut'n'paste (like "#ifdef __ARCH_WANT_SYNC_FILE_RANGE2")

Add new syscalls from 286 (preadv) to 434 (pidfd_open).

Remove obsolete syscalls 1204 (open) to 1079 (fork).

Signed-off-by: Laurent Vivier <[email protected]>
Reviewed-by: Alistair Francis <[email protected]>
Reviewed-by: Richard Henderson <[email protected]>
Message-Id: <20200316085620[email protected]>