x86/tlb: Move __flush_tlb() out of line

cpu_tlbstate is exported because various TLB-related functions need
access to it, but cpu_tlbstate is sensitive information which should
only be accessed by well-contained kernel functions and not be directly
exposed to modules.

As a first step, move __flush_tlb() out of line and hide the native
function. The latter can be static when CONFIG_PARAVIRT is disabled.

Consolidate the namespace while at it and remove the pointless extra
wrapper in the paravirt code.

No functional change.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Borislav Petkov <bp@suse.de>
Reviewed-by: Alexandre Chartre <alexandre.chartre@oracle.com>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/20200421092559.246130908@linutronix.de

arch/x86/platform/uv/tlb_uv.c

@@ -293,7 +293,7 @@ static void bau_process_message(struct msg_desc *mdp, struct bau_control *bcp,
 	 * This must be a normal message, or retry of a normal message
 	 */
 	if (msg->address == TLB_FLUSH_ALL) {
-		local_flush_tlb();
+		flush_tlb_local();
 		stat->d_alltlb++;
 	} else {
 		__flush_tlb_one_user(msg->address);