iwlwifi: constify another argument of iwl_print_hex_dump()

This is needed when enabling debugfs as it passes a const in which
would otherwise be dropped.

Sponsored by:	The FreeBSD Foundation
MFC after:	3 days

sys/contrib/dev/iwlwifi/iwl-debug.c

@@ -115,7 +115,11 @@ iwl_have_debug_level(enum iwl_dl level)
 /* Passing the iwl_drv * in seems pointless. */
 void
 iwl_print_hex_dump(void *drv __unused, enum iwl_dl level,
+#if defined(__linux__)
     const char *prefix, uint8_t *data, size_t len)
+#elif defined(__FreeBSD__)
+    const char *prefix, const uint8_t *data, size_t len)
+#endif
 {
 
 	/* Given we have a level, check for it. */

sys/contrib/dev/iwlwifi/iwl-debug.h

@@ -109,7 +109,11 @@ void __iwl_err(struct device *, enum iwl_err_mode, const char *, ...);
 
 #ifdef CONFIG_IWLWIFI_DEBUG
 bool iwl_have_debug_level(enum iwl_dl);
+#if defined(__linux__)
 void iwl_print_hex_dump(void *, enum iwl_dl, const char *, uint8_t *, size_t);
+#elif defined(__FreeBSD__)
+void iwl_print_hex_dump(void *, enum iwl_dl, const char *, const uint8_t *, size_t);
+#endif
 void __iwl_dbg(struct device *, u32, bool, const char *, const char *fmt, ...);
 
 #define	IWL_DPRINTF_DEV_PREFIX(_dev, _e, _prefix, _fmt, ...)		\