test_bpf: Rename second ALU64_SMOD_X to ALU64_SMOD_K

Currently, there are two test cases with same name
"ALU64_SMOD_X: -7 % 2 = -1", the first one is right,
the second one should be ALU64_SMOD_K because its
code is BPF_ALU64 | BPF_MOD | BPF_K.

Before:
test_bpf: torvalds#170 ALU64_SMOD_X: -7 % 2 = -1 jited:1 4 PASS
test_bpf: torvalds#171 ALU64_SMOD_X: -7 % 2 = -1 jited:1 4 PASS

After:
test_bpf: torvalds#170 ALU64_SMOD_X: -7 % 2 = -1 jited:1 4 PASS
test_bpf: torvalds#171 ALU64_SMOD_K: -7 % 2 = -1 jited:1 4 PASS

Fixes: daabb2b ("bpf/tests: add tests for cpuv4 instructions")
Signed-off-by: Tiezhu Yang <[email protected]>
Acked-by: Yonghong Song <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Alexei Starovoitov <[email protected]>
Signed-off-by: Andrii Nakryiko <[email protected]>

Author: seehearfeel

lib/test_bpf.c

@@ -6277,7 +6277,7 @@ static struct bpf_test tests[] = {
 	},
 	/* BPF_ALU64 | BPF_MOD | BPF_K off=1 (SMOD64) */
 	{
-		"ALU64_SMOD_X: -7 % 2 = -1",
+		"ALU64_SMOD_K: -7 % 2 = -1",
 		.u.insns_int = {
 			BPF_LD_IMM64(R0, -7),
 			BPF_ALU64_IMM_OFF(BPF_MOD, R0, 2, 1),