gcc-15: add '__nonstring' markers to byte arrays

All of these cases are perfectly valid and good traditional C, but hit
by the "you're not NUL-terminating your byte array" warning.

And none of the cases want any terminating NUL character.

Mark them __nonstring to shut up gcc-15 (and in the case of the ak8974
magnetometer driver, I just removed the explicit array size and let gcc
expand the 3-byte and 6-byte arrays by one extra byte, because it was
the simpler change).

Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Author: torvalds

drivers/iio/magnetometer/ak8974.c

@@ -535,8 +535,8 @@ static int ak8974_detect(struct ak8974 *ak8974)
 				       fab_data2, sizeof(fab_data2));
 
 		for (i = 0; i < 3; ++i) {
-			static const char axis[3] = "XYZ";
-			static const char pgaxis[6] = "ZYZXYX";
+			static const char axis[] = "XYZ";
+			static const char pgaxis[] = "ZYZXYX";
 			unsigned offz = le16_to_cpu(fab_data2[i]) & 0x7F;
 			unsigned fine = le16_to_cpu(fab_data1[i]);
 			unsigned sens = le16_to_cpu(fab_data1[i + 3]);

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 unsigned char nibbles[16] __nonstring = "0AB3D56GH9:K<MN?";
 
 	do {
 		if (data[count] == nibbles[data[count] & 0xf])

drivers/net/wireless/ath/carl9170/fw.c

@@ -15,7 +15,7 @@
 #include "fwcmd.h"
 #include "version.h"
 
-static const u8 otus_magic[4] = { OTUS_MAGIC };
+static const u8 otus_magic[4] __nonstring = { OTUS_MAGIC };
 
 static const void *carl9170_fw_find_desc(struct ar9170 *ar, const u8 descid[4],
 	const unsigned int len, const u8 compatible_revision)

fs/cachefiles/key.c

@@ -8,7 +8,7 @@
 #include <linux/slab.h>
 #include "internal.h"
 
-static const char cachefiles_charmap[64] =
+static const char cachefiles_charmap[64] __nonstring =
 	"0123456789"			/* 0 - 9 */
 	"abcdefghijklmnopqrstuvwxyz"	/* 10 - 35 */
 	"ABCDEFGHIJKLMNOPQRSTUVWXYZ"	/* 36 - 61 */