input/joystick: magellan: Mark __nonstring look-up table

JIRA: https://issues.redhat.com/browse/RHEL-101770
Upstream Status: since v6.15
Tested: with the hid-tools test suite and some hardware

commit 936a25e
Author: Kees Cook <kees@kernel.org>
Date:   Wed Apr 16 10:45:17 2025 -0700

    input/joystick: magellan: Mark __nonstring look-up table

    GCC 15's new -Wunterminated-string-initialization notices that the
    16 character lookup table "nibbles" (which is not used as a C-String)
    needs to be marked as "nonstring":

    drivers/input/joystick/magellan.c: In function 'magellan_crunch_nibbles':
    drivers/input/joystick/magellan.c:51:44: warning: initializer-string for array of 'unsigned char' truncates NUL terminator but destination lacks 'nonstring' attribute (17 chars into 16 available) [-Wunterminated-string-initialization]
       51 |         static unsigned char nibbles[16] = "0AB3D56GH9:K<MN?";
          |                                            ^~~~~~~~~~~~~~~~~~

    Add the annotation and While at it, mark the table as const too.

    Signed-off-by: Kees Cook <kees@kernel.org>
    Link: https://lore.kernel.org/r/20250416174513.work.662-kees@kernel.org
    Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>

Signed-off-by: Benjamin Tissoires <benjamin.tissoires@redhat.com>

Author: bentiss

drivers/input/joystick/magellan.c

@@ -48,7 +48,7 @@ struct magellan {
 
 static int magellan_crunch_nibbles(unsigned char *data, int count)
 {
-	static unsigned char nibbles[16] = "0AB3D56GH9:K<MN?";
+	static const unsigned char nibbles[16] __nonstring = "0AB3D56GH9:K<MN?";
 
 	do {
 		if (data[count] == nibbles[data[count] & 0xf])