mt76: update to the latest version, fixes a build error on some platforms

Signed-off-by: Felix Fietkau <nbd@nbd.name>

package/kernel/mt76/Makefile

@@ -1,7 +1,7 @@
 include $(TOPDIR)/rules.mk
 
 PKG_NAME:=mt76
-PKG_VERSION:=2016-11-05
+PKG_VERSION:=2016-12-15
 PKG_RELEASE=1
 
 PKG_LICENSE:=GPLv2
@@ -10,7 +10,7 @@ PKG_LICENSE_FILES:=
 PKG_SOURCE_URL:=https://github.com/openwrt/mt76
 PKG_SOURCE_PROTO:=git
 PKG_SOURCE_SUBDIR:=$(PKG_NAME)-$(PKG_VERSION)
-PKG_SOURCE_VERSION:=892543eb7942990a06129c554125402cfb8e358c
+PKG_SOURCE_VERSION:=7ce4368c3d508b61993466fa5a13a3b5929bde4b
 PKG_SOURCE:=$(PKG_NAME)-$(PKG_VERSION)-$(PKG_SOURCE_VERSION).tar.xz
 
 PKG_MAINTAINER:=Felix Fietkau <nbd@nbd.name>