Bluetooth: vhci: Avoid needless snprintf() calls

Avoid double-copying of string literals. Use a "const char *" for each
string instead of copying from .rodata into stack and then into the skb.
We can go directly from .rodata to the skb.

This also works around a Clang bug (that has since been fixed[1]).

Reported-by: kernel test robot <lkp@intel.com>
Closes: https://lore.kernel.org/oe-kbuild-all/202401250927.1poZERd6-lkp@intel.com/
Fixes: ab4e4380 ("Bluetooth: Add vhci devcoredump support")
Link: https://github.com/llvm/llvm-project/commit/ea2e66aa8b6e363b89df66dc44275a0d7ecd70ce

 [1]
Cc: stable@vger.kernel.org
Signed-off-by: Kees Cook <kees@kernel.org>
Reviewed-by: Nathan Chancellor <nathan@kernel.org>
Reviewed-by: Josh Poimboeuf <jpoimboe@kernel.org>
Signed-off-by: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>