Compiler Attributes: auxdisplay: panel: use __nonstring

Let gcc know these arrays are not meant to be NUL-terminated
by annotating them with the new __nonstring variable attribute;
and remove the comment since it conveys the same information.

Tested-by: Sedat Dilek <sedat.dilek@gmail.com> # on top of v4.19-rc5, clang 7
Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
Reviewed-by: Luc Van Oostenryck <luc.vanoostenryck@gmail.com>
Signed-off-by: Miguel Ojeda <miguel.ojeda.sandonis@gmail.com>

drivers/auxdisplay/panel.c

@@ -155,10 +155,9 @@ struct logical_input {
 			int release_data;
 		} std;
 		struct {	/* valid when type == INPUT_TYPE_KBD */
-			/* strings can be non null-terminated */
-			char press_str[sizeof(void *) + sizeof(int)];
-			char repeat_str[sizeof(void *) + sizeof(int)];
-			char release_str[sizeof(void *) + sizeof(int)];
+			char press_str[sizeof(void *) + sizeof(int)] __nonstring;
+			char repeat_str[sizeof(void *) + sizeof(int)] __nonstring;
+			char release_str[sizeof(void *) + sizeof(int)] __nonstring;
 		} kbd;
 	} u;
 };