brcm80211: remove an unneeded NULL check

This code causes a static checker warning because "pi" gets dereferenced
before it is checked.  The dereference is inside the write_phy_reg()
function which is called from wlc_phy_write_txmacreg_nphy().

This code is only called from wlc_phy_init_nphy() and "pi" is a
valid pointer so we can remove the check for NULL.

Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Acked-by: Arend van Spriel <arend@broadcom.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
diff --git a/drivers/net/wireless/brcm80211/brcmsmac/phy/phy_n.c b/drivers/net/wireless/brcm80211/brcmsmac/phy/phy_n.c
index 13b2615..3667181 100644
--- a/drivers/net/wireless/brcm80211/brcmsmac/phy/phy_n.c
+++ b/drivers/net/wireless/brcm80211/brcmsmac/phy/phy_n.c
@@ -14358,7 +14358,7 @@
 
 	wlc_phy_write_txmacreg_nphy(pi, holdoff, delay);
 
-	if (pi && pi->sh && (pi->sh->_rifs_phy != rifs))
+	if (pi->sh && (pi->sh->_rifs_phy != rifs))
 		pi->sh->_rifs_phy = rifs;
 }