wifi: b43legacy: remove unused freq_r3A_value function

clang with W=1 reports
drivers/net/wireless/broadcom/b43legacy/radio.c:1713:5: error:
  unused function 'freq_r3A_value' [-Werror,-Wunused-function]
u16 freq_r3A_value(u16 frequency)
    ^
This function is not used so remove it.
Signed-off-by: Tom Rix <trix@redhat.com>
Acked-by: Larry Finger <Larry.Finger@lwfinger.net>
Signed-off-by: Kalle Valo <kvalo@kernel.org>
Link: https://lore.kernel.org/r/20230324135022.2649735-1-trix@redhat.com

drivers/net/wireless/broadcom/b43legacy/radio.c

@@ -1709,23 +1709,6 @@ u16 b43legacy_radio_init2050(struct b43legacy_wldev *dev)
 	return ret;
 }
 
-static inline
-u16 freq_r3A_value(u16 frequency)
-{
-	u16 value;
-
-	if (frequency < 5091)
-		value = 0x0040;
-	else if (frequency < 5321)
-		value = 0x0000;
-	else if (frequency < 5806)
-		value = 0x0080;
-	else
-		value = 0x0040;
-
-	return value;
-}
-
 int b43legacy_radio_selectchannel(struct b43legacy_wldev *dev,
 				  u8 channel,
 				  int synthetic_pu_workaround)