staging: rtl8192u: remove unnecessary return in r8190_rtl8256.c

remove the unnecessary return at the end of function
phy_set_rf8256_ofdm_tx_power(), reported by scripts/checkpatch.pl.
Signed-off-by: Du Cheng <ducheng2@gmail.com>
Link: https://lore.kernel.org/r/20210219150527.8358-2-ducheng2@gmail.comSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/staging/rtl8192u/r8190_rtl8256.c

@@ -291,5 +291,4 @@ void phy_set_rf8256_ofdm_tx_power(struct net_device *dev, u8 powerlevel)
 		}
 		rtl8192_setBBreg(dev, RegOffset[index], 0x7f7f7f7f, writeVal);
 	}
-	return;
 }