modules: update OpenWrt

13eeee7b2b mt76: update to the latest version
ac1ce25671 OpenWrt v18.06.2: revert to branch defaults
a02809f61b OpenWrt v18.06.2: adjust config defaults
cddd7b4c77 base-files: config_get: prevent filename globbing
e6162b2127 dnsmasq: backport missing braces fix
d4178c8f47 build: fix umask detection bashism
b98b55a64f build: fix STAGING_DIR cleaning for packages
e6c2f3feb1 ar71xx: use correct wan mac address for the TP-Link Archer C7 v4
2c7a1ccaea ar71xx: Add usb drivers in Archer C7 v4/v5 images
39c3b5139f openssl: bump to 1.0.2q
80ed6ebc56 dnsmasq: backport upstream static lease fix
4f2199f528 wireguard: bump to 0.0.20190123
8c105c62e4 wireguard: Update to snapshot 0.0.20181218
1447924c95 mbedtls: update to 2.14.1 for 18.06
e5a0b6cde0 uhttpd: disable concurrent requests by default
11bfb39e39 kernel: bump 4.14 to 4.14.95
dd5fa217dc kernel: bump 4.9 to 4.9.152
91d3b87353 uboot-fritz4040: fix crash caused by interaction with gcc 7.1+

Compile-tested: ar71xx-generic, mpc85xx-generic, ramips-mt7621
Runtime-tested: ramips-mt7621 (D-Link DIR860L)