drivers/net: Remove unnecessary returns from void function()s

This patch removes from drivers/net/ all the unnecessary
return; statements that precede the last closing brace of
void functions.

It does not remove the returns that are immediately
preceded by a label as gcc doesn't like that.

It also does not remove null void functions with return.

Done via:
$ grep -rP --include=*.[ch] -l "return;\n}" net/ | \
  xargs perl -i -e 'local $/ ; while (<>) { s/\n[ \t\n]+return;\n}/\n}/g; print; }'

with some cleanups by hand.

Compile tested x86 allmodconfig only.

Signed-off-by: Joe Perches <joe@perches.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/wireless/ath/ath9k/calib.c

@@ -86,7 +86,6 @@ static void ath9k_hw_update_nfcal_hist_buffer(struct ath9k_nfcal_hist *h,
 				ath9k_hw_get_nf_hist_mid(h[i].nfCalBuffer);
 		}
 	}
-	return;
 }
 
 static bool ath9k_hw_get_nf_thresh(struct ath_hw *ah,