crypto: x86/chacha20 - Avoid spurious jumps to other functions

stable inclusion
from stable-v5.10.118
commit a59450656bcda7fbee9f892d5a65715ad846ce29
category: bugfix
bugzilla: https://gitee.com/openeuler/kernel/issues/I5L686

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=a59450656bcda7fbee9f892d5a65715ad846ce29

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[ Upstream commit 4327d168 ]

The chacha_Nblock_xor_avx512vl() functions all have their own,
identical, .LdoneN label, however in one particular spot {2,4} jump to
the 8 version instead of their own. Resulting in:

  arch/x86/crypto/chacha-x86_64.o: warning: objtool: chacha_2block_xor_avx512vl() falls through to next function chacha_8block_xor_avx512vl()
  arch/x86/crypto/chacha-x86_64.o: warning: objtool: chacha_4block_xor_avx512vl() falls through to next function chacha_8block_xor_avx512vl()

Make each function consistently use its own done label.
Reported-by: NStephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: NPeter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: NMartin Willi <martin@strongswan.org>
Signed-off-by: NHerbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: NSasha Levin <sashal@kernel.org>
Signed-off-by: NZheng Zengkai <zhengzengkai@huawei.com>
Acked-by: NXie XiuQi <xiexiuqi@huawei.com>

arch/x86/crypto/chacha-avx512vl-x86_64.S

@@ -172,7 +172,7 @@ SYM_FUNC_START(chacha_2block_xor_avx512vl)
 	# xor remaining bytes from partial register into output
 	mov		%rcx,%rax
 	and		$0xf,%rcx
-	jz		.Ldone8
+	jz		.Ldone2
 	mov		%rax,%r9
 	and		$~0xf,%r9
 
@@ -438,7 +438,7 @@ SYM_FUNC_START(chacha_4block_xor_avx512vl)
 	# xor remaining bytes from partial register into output
 	mov		%rcx,%rax
 	and		$0xf,%rcx
-	jz		.Ldone8
+	jz		.Ldone4
 	mov		%rax,%r9
 	and		$~0xf,%r9