The __string() and __assign_str() helper macros of the TRACE_EVENT() macro
are going through some optimizations where only the source string of
__string() will be used and the __assign_str() source will be ignored and
later removed.

To make sure that there's no issues, a new check is added between the
__string() src argument and the __assign_str() src argument that does a
strcmp() to make sure they are the same string.

The hclgevf trace events have:

  __assign_str(devname, &hdev->nic.kinfo.netdev->name);

Which triggers the warning:

hclgevf_trace.h:34:39: error: passing argument 1 of ‘strcmp’ from incompatible pointer type [-Werror=incompatible-pointer-types]
   34 |                 __assign_str(devname, &hdev->nic.kinfo.netdev->name);
 [..]
arch/x86/include/asm/string_64.h:75:24: note: expected ‘const char *’ but argument is of type ‘char (*)[16]’
   75 | int strcmp(const char *cs, const char *ct);
      |            ~~~~~~~~~~~~^~

Because __assign_str() now has:

	WARN_ON_ONCE(__builtin_constant_p(src) ?		\
		     strcmp((src), __data_offsets.dst##_ptr_) :	\
		     (src) != __data_offsets.dst##_ptr_);	\

The problem is the '&' on hdev->nic.kinfo.netdev->name. That's because
that name is:

	char			name[IFNAMSIZ]

Where passing an address '&' of a char array is not compatible with strcmp().

The '&' is not necessary, remove it.

Link: https://lore.kernel.org/linux-trace-kernel/20240313093454.3909afe7@gandalf.local.home

Cc: netdev <netdev@vger.kernel.org>
Cc: Yisen Zhuang <yisen.zhuang@huawei.com>
Cc: Salil Mehta <salil.mehta@huawei.com>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Eric Dumazet <edumazet@google.com>
Cc: Jakub Kicinski <kuba@kernel.org>
Cc: Yufeng Mo <moyufeng@huawei.com>
Cc: Huazhong Tan <tanhuazhong@huawei.com>
Cc: stable@vger.kernel.org
Acked-by: Paolo Abeni <pabeni@redhat.com>
Reviewed-by: Jijie Shao <shaojijie@huawei.com>
Fixes: d8355240 ("net: hns3: add trace event support for PF/VF mailbox")
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>