staging: brcm80211: Fix memory leak after kmalloc failure

This error was spotted by cppcheck:

drivers/staging/brcm80211/phy/wlc_phy_lcn.c:4053: error: Memory leak: ptr

Cc: Brett Rudley <brudley@broadcom.com>
Cc: Henry Ptasinski <henryp@broadcom.com>
Cc: linux-wireless@vger.kernel.org
Cc: devel@driverdev.osuosl.org
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Stefan Weil <weil@mail.berlios.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

drivers/staging/brcm80211/brcmsmac/phy/wlc_phy_lcn.c

@@ -4051,6 +4051,7 @@ wlc_lcnphy_a1(phy_info_t *pi, int cal_type, int num_levels, int step_size_lg2)
 
 	phy_c32 = kmalloc(sizeof(u16) * 20, GFP_ATOMIC);
 	if (NULL == phy_c32) {
+		kfree(ptr);
 		return;
 	}
 	phy_c26 = read_phy_reg(pi, 0x6da);