SUNRPC: Clean up initialisation of the struct rpc_rqst

commit 9dc6edcf676fe188430e8b119f91280bbf285163 upstream.

Move the initialisation back into xprt.c.

Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
Cc: Yihao Wu <wuyihao@linux.alibaba.com>
Cc: Caspar Zhang <caspar@linux.alibaba.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>