wifi: cfg80211: Add KHZ_PER_GHZ to units.h and reuse

The KHZ_PER_GHZ might be used by others (with the name aligned
with similar constants). Define it in units.h and convert
wireless to use it.
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Reviewed-by: Simon Horman <horms@kernel.org>
Link: https://msgid.link/20240215154136.630029-1-andriy.shevchenko@linux.intel.comSigned-off-by: Johannes Berg <johannes.berg@intel.com>

include/linux/units.h

@@ -24,10 +24,13 @@
 #define NANOHZ_PER_HZ		1000000000UL
 #define MICROHZ_PER_HZ		1000000UL
 #define MILLIHZ_PER_HZ		1000UL
+
 #define HZ_PER_KHZ		1000UL
-#define KHZ_PER_MHZ		1000UL
 #define HZ_PER_MHZ		1000000UL
 
+#define KHZ_PER_MHZ		1000UL
+#define KHZ_PER_GHZ		1000000UL
+
 #define MILLIWATT_PER_WATT	1000UL
 #define MICROWATT_PER_MILLIWATT	1000UL
 #define MICROWATT_PER_WATT	1000000UL

net/wireless/reg.c

@@ -57,6 +57,8 @@
 #include <linux/verification.h>
 #include <linux/moduleparam.h>
 #include <linux/firmware.h>
+#include <linux/units.h>
+
 #include <net/cfg80211.h>
 #include "core.h"
 #include "reg.h"
@@ -1289,20 +1291,17 @@ static bool is_valid_rd(const struct ieee80211_regdomain *rd)
 static bool freq_in_rule_band(const struct ieee80211_freq_range *freq_range,
 			      u32 freq_khz)
 {
-#define ONE_GHZ_IN_KHZ	1000000
 	/*
 	 * From 802.11ad: directional multi-gigabit (DMG):
 	 * Pertaining to operation in a frequency band containing a channel
 	 * with the Channel starting frequency above 45 GHz.
 	 */
-	u32 limit = freq_khz > 45 * ONE_GHZ_IN_KHZ ?
-			20 * ONE_GHZ_IN_KHZ : 2 * ONE_GHZ_IN_KHZ;
+	u32 limit = freq_khz > 45 * KHZ_PER_GHZ ? 20 * KHZ_PER_GHZ : 2 * KHZ_PER_GHZ;
 	if (abs(freq_khz - freq_range->start_freq_khz) <= limit)
 		return true;
 	if (abs(freq_khz - freq_range->end_freq_khz) <= limit)
 		return true;
 	return false;
-#undef ONE_GHZ_IN_KHZ
 }
 
 /*