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>