brcmsmac: change pa_gain for bcm4313 iPA

The function wlc_lcnphy_load_tx_gain_table() has a target PA
gain specified for the iPA variant of the bcm4313. This gain
value is reduced to avoid PA distortion. The if-statement is
removed because it was rather redundant in the first place.
Please note that this patch does not provide full iPA support.

Cc: Jonas Gorski <jogo@openwrt.org>
Tested-by: David Herrmann <dh.herrmann@gmail.com>
Reviewed-by: Pieter-Paul Giesberts <pieterpg@broadcom.com>
Reviewed-by: Hante Meuleman <meuleman@broadcom.com>
Signed-off-by: Arend van Spriel <arend@broadcom.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

drivers/net/wireless/brcm80211/brcmsmac/phy/phy_lcn.c

@@ -4282,13 +4282,10 @@ wlc_lcnphy_load_tx_gain_table(struct brcms_phy *pi,
 	u16 pa_gain;
 	u16 gm_gain;
 
-	if (CHSPEC_IS5G(pi->radio_chanspec))
-		pa_gain = 0x70;
-	else
-		pa_gain = 0x70;
-
 	if (pi->sh->boardflags & BFL_FEM)
 		pa_gain = 0x10;
+	else
+		pa_gain = 0x60;
 	tab.tbl_id = LCNPHY_TBL_ID_TXPWRCTL;
 	tab.tbl_width = 32;
 	tab.tbl_len = 1;