[PATCH v2 0/2] RISC-V: Don't use a global include guard for uapi/asm/syscalls.

[Palmer Dabbelt]

It turns out that we weren't actually hooking sys_riscv_flush_icache
into the syscall table, which results in any flush_icache() call that
escapes the vDSO to silently do nothing.

Changes since v1:

* sys_riscv_flush_icache is now defined even when SMP=n, which allows
  this patch set to build against SMP=n and SMP=y.