wifi: virt_wifi: Add __nonstring annotations for unterminated strings

When a character array without a terminating NUL character has a static
initializer, GCC 15's -Wunterminated-string-initialization will only
warn if the array lacks the "nonstring" attribute[1]. Mark the arrays
with __nonstring to and correctly identify the char array as "not a C
string" and thereby eliminate the warning.

Link: https://gcc.gnu.org/bugzilla/show_bug.cgi?id=117178

 [1]
Signed-off-by: Kees Cook <kees@kernel.org>
Link: https://patch.msgid.link/20250311225604.it.926-kees@kernel.org


Signed-off-by: Johannes Berg <johannes.berg@intel.com>